Question

If A:B=7:8 and B:C=10:17, find A:B:C.

Answer 1

A : B = 7 : 8 , B : C = 10 : 17

A/ B = 7/ 8 ---(1) , B/ C = 10/ 17 --(2)

from (2)

B = 10C/ 17

from(1)

A = 7B/ 8 = 7 (10C/ 17)/ 8

A = 70C/ 136 = 35C/ 68

Thus A = 35C/ 68

then

A : B : C = 35C/ 68 : 10C/ 17 : C

= 35/68 : 10/ 17 : 1

L.C.M ( 68 , 17 ,1 ) = 68

so then

A : B : C = 35 : 10 × 4 : 68

A : B : C = 35 : 40 : 68

Answer: A : B : C = 35 : 40 : 68
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