Question

Plsss helpppp I’m stuck

Answer 1

C=15
...................

Answer 2

Answer:

b = 2c:  Ben's age is twice Cindy's.  So Cindy is 15 years old

(a + b + c) / 3 = 28: Their average age is 28  This tells us nothing as we already have Anne, Ben and Cindy's ages.  It does however give us a quick way to check the answers:

$\frac{a + b + c}{3} = 28\\\frac{39 + 30 + 15}{3} = 28\\\frac{84}{3} = 28$

Correct, so we know values found are correct.