If a ∶ b = 5 ∶ 1, then what is the value of 3a + 4b ∶ 3a - 4b?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 19 : 11.
If a ∶ b = 5 ∶ 1
Let a = 5x and b = x
The value of 3a + 4b ∶ 3a - 4b
⇒ (3 × 5x + 4 × x) : (3 × 5x - 4 × x)
⇒ (15x + 4x) : (15x - 4x)
⇒ 19x : 11x
⇒ 19 : 11