Quiz Time pls help me A girl went to school the teacher ask

Quiz Time pls help me

A girl went to school & the teacher asked how old are you? She replied I don\'t know, bt I know that I\'m half my mother\'s age. The teacher asked ok how old is your mother? She said I don\'t know but I know that my Dad is 5 yrs older than my mother. Teacher, how old is yor dad? She said I don\'t know but I know that if we add our ages the answer is 100 yrs...

1. How old is the girl?
2. How old is the mum?
3. How old is the dad?

Solution

let her mothers age be x

and her age is half of her mothers = x/2

her fathers age = x+5

now also she told that sum of all their ages = 100

x+x+5 +x/2 = 100

(4x+10+x)/2 = 100

5x+10 = 200

5x= 190

x = 38

1) girl s age = x/2 = 19

2) her mum age x = 38

3) her fatehr age = x+5 = 43