Question

the ratio between two numbers is 3 : 4 and their sum is 420. what is the greater of the two numbers? 175 200 240 315

Answer 1

$\frac{x}{y} = \frac{3}{4} \\ 4x = 3y \\ 4x - 3y = 0 \\ .............................. \\ x + y = 420 \\ 3x + 3y = 1260 \\ .............................. \\ 4x - 3y = 0 \\ 3x + 3y = 1260 \\..............................\\ 7x = 1260 \\ x = 180 \\ y = 240$

Greater of the two numbers 240.