Question

If x:y=3:5 find the ratio 3×+4y:8x +5y​

Answer 1

I had to try a couple of times to get the answer. The answer is of ratio 29:49

Answer 2

29: 49

Explanation:

Since x:y= 3:5,

`(x)/(y) = (3)/(5)`

Cross multiply:

`5x = 3y`

Divide by 5 on both sides:

`x = (3)/(5) y`

`(3x + 4y)/(8x + 5y) \\ = (3( (3)/(5)y) + 4y )/(8( (3)/(5)y) + 5y ) \\ = ( (9)/(5)y + 4y )/( (24)/(5)y + 5y ) \\ = (9y + 5(4y))/(24y + 5(5y)) \\ = (9y + 20y)/(24y + 25y) \\ = (29y)/(49y) \\ = (29)/(49)`

Thus, 3x+4y: 8x+5y= 29: 49.