Question

If a : b = 3:4, b:c = 5:7 and the average of a, b and c is 21, what are the values of a, b and c​

Answer 1

Answer:

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Step-by-step explanation:

Answer 2

Step-by-step explanation:

A:B=3:4

Let A be 3k and B be 4k.

B:C=5:7

Let B be 5x and C be 7x

4k=5x

x=

5

4k

A:B:C=3k:4k:7x=3k:4k:7(

5

4k

)=15k:20k:28k=15:20:28

Hence A:B:C=15:20:28