Age math problem

Question

Bob's age is 4 times Michelle's age and Sara's age is half Bob's age. If their ages add up to 84, what is Michelle's age?



Answer 1

Using B for bob's age, M for Michelle's age and S for Sara's age:

B = 4M so M = 0.25B and S = 0.5B

And B + M + S = 84

So B + 0.25B + 0.5B = 84

1.75B = 84

B = 48

Again, M = 0.25B

So M = 0.25(48) = 12