Question

Mark (✓) against the correct answer
If (x : y) = 3 : 4, then (7x + 3y) : (7x − 3y) = ?

(a) 7 : 3
(b) 5 : 2
(c) 11 : 3
(d) 14 : 9

Answer 1

(c) 11 : 3

$$\begin{gathered} \mathrm{We}\mathrm{have}x=\frac{3}{4}y \\ \mathrm{Now},\frac{7x+3y}{7x-3y}=\frac{7\times {\displaystyle \frac{3}{4}}y+3y}{7\times {\displaystyle \frac{3}{4}}y-3y}=\frac{21y+12y}{21y-12y} \\ =\frac{33y}{9y}=\frac{11}{3} \end{gathered}$$