Question

If x: y = 3:8, then find the value of (5x + 7y) : (8x + 11y).
(B) 71 : 14
(C) 91: 71
(D) 14:71
(A) 71:91
(E) None of these​

Answer 1

Answer:

none of these.

Step-by-step explanation:

We rewrite the original ratio as such.

x/y=3/8

We cross-multiply to give:

3y=8x

Now, we can simply express x in terms of y or y in terms of x. I’ll opt to do the latter.

Dividing by 3 gives;

y=8x/3

We substitute this into (5x+7y) :(8x+11y).

We now get (5x+56x/3):(8x+121x/3)

This gives ;(71x/3):(125x/3). We now simplify to get 71/125.