Question

If a : b = 2 : 1, the value of (7a + 4b) : (5a – 2b) is ______.

Options

• 9 : 4

• 4 : 9

• 11 : 3

• 3 : 11

Answer 1

If a : b = 2 : 1, the value of (7a + 4b) : (5a – 2b) is 9 : 4.

Explanation:

Given a : b = 2 : 1

`\implies a/b = 2/1`  ...(1)

∴ `(7a + 4b)/(5a - 2b) = (7a + 4(a/2))/(5a - 2(a/2))`

= `(7a + 2a)/(5a - a)`

= `(9a)/(4a)`

= `9/4`

= 9 : 4