A cold water tap can fill a bath in 6 minutes while a hot water tap can fill it in 12 minutes. The drainage pipe...

A cold water tap can fill a bath in 6 minutes while a hot water tap can fill it in 12 minutes. The drainage pipe can empty the bath in 8 minutes. All the three are opened fully for 3 minutes and then hot water tap is closed. How many more minutes will it take to fill the bath?

---

Fraction filled when all three are open in 1 minute.
= 1/6 + 1/12 - 1/8 = 1/8
Fraction filled in 3 minutes = 1/8 x 3 = 3/8
Fraction remaining = 5/8
Fraction filled per minute with hot water tap closed
= 1/6 - 1/8 = 1/24
Time taken to fill 5/8 of bath
= (5/8)/(1/24)
= 5/8 x 24
= 15 minutes.

---

Githiari answered the question on April 3, 2019 at 17:35

Exams With Marking Schemes

• Grade 1
• Grade 2
• Grade 3
• Grade 4
• Grade 5
• Grade 6
• Grade 7
• Grade 8
• Grade 9
• PP1
• PP2
• Playgroup
• Form 1
• Form 2
• Form 3
• Form 4

Related Questions

---

• An estate is drawn to scale on a grid of 1 cm squares with a total area of 35 cm² .If the actual area of... (Solved)
  

  An estate is drawn to scale on a grid of 1 cm squares with a total area of 35 cm² .If the actual area of the estate is 560 hectares, calculate the linear scale of the map.
  
  

  Date posted: April 3, 2019 .    Answers (1)

• The sum of the first 8 terms of an AP is 236 and the sum of the first 6 terms of the same series is... (Solved)
  

  The sum of the first 8 terms of an AP is 236 and the sum of the first 6 terms of the same series is 147. Find the sum of the first 12 terms of the series.
  

  Date posted: April 3, 2019 .    Answers (1)

• A mixed day and boarding secondary school has a student depositions population of 630. The ratio of girls to boys is 3:4. The school has... (Solved)
  

  A mixed day and boarding secondary school has a student depositions population of 630. The ratio of girls to boys is 3:4. The school has 350 boarders some of whom are boys and others are girls. A student is picked at random from the school. Find the probability that the student is
  a) a boarder
  b) a girl and not a boarder.
  

  Date posted: April 3, 2019 .    Answers (1)

• Juma deposited sh 16000 in a bank which paid compound interest at the of 12 percent per annum. At the end of five years, he... (Solved)
  

  Juma deposited sh 16000 in a bank which paid compound interest at the of 12 percent per annum. At the end of five years, he withdrew all his money. Determine how much money he withdrew.
  
  

  Date posted: April 3, 2019 .    Answers (1)

• Describe the procedure to be followed when constructing ungrouped frequency distribution table (Solved)
  

  Describe the procedure to be followed when constructing ungrouped frequency distribution table.

  Date posted: April 3, 2019 .    Answers (1)

• To transport 100 people and 3500 kg to a wedding a company has type A vehicles which take 10 people and 200kg each and type... (Solved)
  

  To transport 100 people and 3500 kg to a wedding a company has type A vehicles which take 10 people and 200kg each and type B which take 6 people and 300kg each. They must not use more
  than 16 vehicles all together.
  (a) Write down 3 inequalities in A and B which are the number of vehicles used and plot them
  in a graph.
  (b) What is the smallest number of vehicles he could use.
  (c) Hire charge for type A is Sh.1000 while hire for type B is Sh.1200 per vehicle. Find the cheapest
  hire charge for the whole function

  Date posted: March 29, 2019 .    Answers (1)

• OAB is a triangle with OA = a , OB = b. R is a point of AB. 2AR = RB. P is on OB... (Solved)
  

  OAB is a triangle with OA = a , OB = b. R is a point of AB. 2AR = RB. P is on OB such that 3OP = 2PB. OR and AP intersect at Y, OY = m OR and AY = nAP. Where m and n are scalars. Express in terms of a and b.
  (i) OR
  (ii)AP
  (b) Find the ratio in which Y divides AP

  Date posted: March 29, 2019 .    Answers (1)

• A rectangular tennis court is 10.5m long and 6m wide. Square tiles of 30cm are fitted on the floor. (a) Calculate the number of tiles needed.... (Solved)
  

  A rectangular tennis court is 10.5m long and 6m wide. Square tiles of 30cm are fitted on the floor.
  (a) Calculate the number of tiles needed.
  (b) Tiles needed for 15 such rooms are packed in cartons containing 20 tiles. How many cartons are
  there in total?
  (c) Each carton costs shs. 800. He spends shs. 100 to transport each 5 cartons. How much would one
  sell each carton to make 20% profit ?

  Date posted: March 29, 2019 .    Answers (1)

• Members of a youth club decided to contribute shs 180,000 to start a company. Two members withdrew their membership and each of the remaining member... (Solved)
  

  Members of a youth club decided to contribute shs 180,000 to start a company. Two members withdrew their membership and each of the remaining member had to pay shs. 24,000 more to meet the same expense. How many members remained?

  Date posted: March 29, 2019 .    Answers (1)

• A right cone with slant height of 15cm and base radius 9cm has a smaller cone of height 6cm chopped off to form a frustum.... (Solved)
  

  A right cone with slant height of 15cm and base radius 9cm has a smaller cone of height 6cm chopped off to form a frustum. Find the volume of the frustum formed

  Date posted: March 29, 2019 .    Answers (1)

• A solid sphere of radius 18cm is to be made from a melted copper wire of radius 0.4mm . Calculate the length of wire in... (Solved)
  

  A solid sphere of radius 18cm is to be made from a melted copper wire of radius 0.4mm . Calculate the length of wire in metres required to make the sphere. (5mks)
  (b) If the density of the wire is 5g/cm³. Calculate the mass of the sphere in kg.

  Date posted: March 29, 2019 .    Answers (1)

• A building contractor has to move 150 tonnes of cement to a site 30km away. He has at his disposal 5 lorries. Two of the... (Solved)
  

  A building contractor has to move 150 tonnes of cement to a site 30km away. He has at his disposal 5 lorries. Two of the lorries have a carrying capacity of 12 tonnes each while each of the remaining can carry 7 tonnes. The cost of operating a 7 tonne lorry is sh. 15 per km and that of operating a 12 tonne lorry is sh. 25 per km. The number of trips by the bigger lorries should be more than twice that made by smaller lorries.
  (a) Represent all the information above as inequalities.
  (b) How should the contractor deploy his fleet in order to minimise the cost of moving the cement?

  Date posted: March 29, 2019 .    Answers (1)

• Given a circle of radius 3 units as shown in the diagram below with its centre at O(-1, 6). If BE and DE are tangents... (Solved)
  

  Given a circle of radius 3 units as shown in the diagram below with its centre at O(-1, 6). If BE and DE are tangents to the circle where E (8,2). Given further that angle DAB = 80⁰.
  
  
  (a) Write down the equation of the circle in the form ax² + bx + cy² + dy + e = 0 where a, b, c, d, e are constants.
  (b) Calculate the length DE.
  (c) Calculate the value of angle BED.
  (d) Calculate the value of angle DCB.

  Date posted: March 29, 2019 .    Answers (1)

• A bag contains x red balls and y yellow balls. Four times the number of red balls is equal to nine times the number of... (Solved)
  

  A bag contains x red balls and y yellow balls. Four times the number of red balls is equal to nine times the number of yellow balls and twice the total number of balls exceeds the number of yellow balls by 44.
  (a) How many balls of each colour are three in the bag?
  (b) If two balls are drawn out of the bag at random one at a time with replacement what is the probability that the two balls are red?

  Date posted: March 29, 2019 .    Answers (1)

• The diagram below represents a bucket that has been placed upside down. The radius of the top surface is 15cm and that of the bottom... (Solved)
  

  The diagram below represents a bucket that has been placed upside down. The radius of the top surface is 15cm and that of the bottom is 40cm. The vertical height of the bucket is 50cm.
  
  
  Determine:-
  (a) The volume of the bucket.
  (b) The curved surface area of the bucket. (leave your answers in terms of π)

  Date posted: March 29, 2019 .    Answers (1)

• Find the co-ordinates of the turning point on the curve of y = x³ – 3x² and distinguish between them. (Solved)
  

  Find the co-ordinates of the turning point on the curve of y = x³ – 3x² and distinguish between them.

  Date posted: March 29, 2019 .    Answers (1)

• Calculate the Area of each of the two segments of y = x(x+1)(x-2) cut off by the x axis. (Solved)
  

  Calculate the Area of each of the two segments of y = x(x+1)(x-2) cut off by the x axis.

  Date posted: March 29, 2019 .    Answers (1)

• The Probabilities that it will either rain or not in 30days from now are 0.5 and 0.6 respectively. Find the probability that in 30 days... (Solved)
  

  The Probabilities that it will either rain or not in 30days from now are 0.5 and 0.6 respectively. Find the probability that in 30 days time.
  a) it will either rain and not.
  b) Neither will not take place.
  c) One Event will take place.

  Date posted: March 29, 2019 .    Answers (1)

• Two towns T and S are 300km apart. Two buses A and B started from T at the same time travelling towards S. Bus B... (Solved)
  

  Two towns T and S are 300km apart. Two buses A and B started from T at the same time travelling towards S. Bus B travelled at an average speed of 10km/hr greater than that of A and reached S 1 ¼ hrs earlier.
  (a) Find the average speed of A.
  (b) How far was A from T when B reached S.

  Date posted: March 29, 2019 .    Answers (1)

• The marks obtained by Form 4 students in Examination were as follows: Using 74.5 as the Assumed mean, calculate: (i) The mean mark (ii) The standard deviation (Solved)
  

  The marks obtained by Form 4 students in Examination were as follows:
  
  
  Using 74.5 as the Assumed mean, calculate:
  (i) The mean mark
  (ii) The standard deviation

  Date posted: March 29, 2019 .    Answers (1)