Question

If `A : B = 3 : 4 , B : C = 5 : 6 " and " C : D = 7 : 8, " then " A : D = `
A. ` 3 : 8`
B. ` 35 : 64`
C. ` 8 : 3`
D. ` 64 : 35`

Answer 1

Correct Answer - B
We have , `A : B = 3 : 4 rArr A/B = 3/4 ` .... (1)
` B : C = 5 : 6 rArr B/C = 5/6 ` .....(2)
` C : D = 7 : 8 rArr C/D = 7/8 ` .....(3)
Now, multiplying (1), (2) and (3) we get,
`A/B xx B/C xx C/D = 3/4 xx 5/6 xx 7/8`
or, ` A/D = 35/64 " or," A : D = 35 : 64`
Hence the required ratio is ` 35 : 64`
` :. ` (b) is correct .