AGE PROBLEM MATHEMATICS

Question

Sue is N years old , her sister is 7 and sue's brother is twice her age . The total of their age is 31 . What is the value of N.

Answer 1

N + 7 + 2N = 31

3N = 31-7 = 24

N = 24/3 = 8 years old = Sue's age

Sue's brother is 2N = 2(8) = 16 years old

Sue's sister is 7 years old

8+7+16 = 31

UNLESS by "Sue's brother is twice 'her' age" you meant twice the sister's age

then N + 7 + 2(7) = 31

N = 31 -21 = 10

Then Sue is 10 years old

sister is 7 years old

brother is 14 years old

10+7+14 = 31

Odds are you meant the 1st answer though

so, go with N=8