The sum of ages of Subbu and Toby us 18years and the difference between their ages is 4years .find their ages

Dear Student,
Let age of subbu be x
let age of toby be y
x+y=18 {Given}
x-y=4 {Given}
Adding above two equations we get
2x=22
x=11
y=18-11
y=7
Therefore age of subbu is 11 years and age of toby is 7 years

Regards