Question

If the sum of Noor's age and Salma's age = 30, 3 years ago Noor's

age was half of Salma's age. Find their present ages

Answer 1

Noor's age is 12 & Salma's age is 18

Explanation:

Noor's age: N

Salma's age: S

`N+S=30` : given

`N - 3 = (S)/(2)` : given

`N = (S)/(2)+3` : isolate "N"

`(S)/(2)+3 + S = 30` : substitute the value of N for N to find the value of "S"

`(S)/(2) + S = 27` : subtract 3 from both sides

`(S)/(2)*2 + S*2 = 27*2` ≡
`S + 2S = 54` : multiply both sides by 2

`3S = 54` : add like values

`(3S)/(3) = (54)/(3)` : divide both sides by 3

S = 18

now insert that value into the initial equation:

`N + 18 = 30`

`N = 12` : subtract 18 from both sides