Question

A is 15 years older then B.Ten years ago,A was four times B's age. What are their age now

Answer 1

let A be x years
let B be y years
 from 1 condition
x=15+y.....(1)
ten years ago
A's age will be x-10 and that of B's will be y-10
x-10=4(y-10)
x-10=4y-40
x-4y=-40+10
x-4y=-30....(2)
put x=15+y in eqn. no. (2)
15+y-4y=-30
15-3y=-30
-3y=-30-15
-3y=-45
y=-45/-3
y=15
put y=15 in eqn. no. (1)
x=15+15
x=30
S.S=[30,15]