Please help solve this hard Math Word Problem

Question

1.) Alice's age is an exact multiple of Betty's age. In eight years, they will both be teenagers. How old are they now?

2.) Colin has two teenage sisters, who are not twins. In three years, the ages of both sisters will be exactly divisible by Colin's age. How old are all three now?

Answer 1

1.)

 

Teenagers  age ranges from 13 to19

so  Alice and Betty's present age must be between 5 to 11 (19-8 =11 and 13-8=5 )

 

 The only numbers in that range that are multiples of each other are 5 and 10. 

 Alice is 10; Betty is 5.

2.)

Colin has two teenage sisters,In three years their age range from(13+3 =16 to 19+3=22)
 two numbers in the range 16 to 22, inclusive, that are both multiples of a number 3 or greater. Those would be 18 and 21, multiples of 3; and 16 and 20, multiples of 4.

Colin may 0 (less than 1), the sisters are 15-3=15 and 21-3=18.

Or Colin may 1, the sisters are 16-3=13 and 20-3= 17.