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If a=b+3, b=c+2, c=2d and d=4, what is the value of 3a - 4b + 2c ?

Class: KCPE

Subject: Mathematics

Topic: Algebra

Lesson Summary

If a=b+3, b=c+2, c=2d and d=4, what is the value of 3a - 4b + 2c ?

A.39
B.40
C.16
D.15



Text Answer


First find the values of a, b and c as follows:

D=4 c=2d=2 x 4= 8

B=c+2 =8+2 =10 a=b+3= 10+3 =13

Substitute the values in the given expression.

3a-4b+2c = 3 x13 – 4 x10 + 2 x8

= 39 – 40 + 16

= 55 – 40 = 15

The correct answer is D (15).

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