SOLUTION: A father who is 42 years old has a son and a daughter. The daughter is three times as old as the son. In 10 years the sum of all their ages will be 100 years. How old are the two s

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Question 1069154: A father who is 42 years old has a son and a daughter. The daughter is three times as old as the son. In 10 years the sum of all their ages will be 100 years. How old are the two siblings at present?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
s, son
d, daugher

The description as a system of equations:
system%28d=3s%2Cs%2B10%2Bd%2B10%2B42%2B10=100%29


s%2Bd=100-42-30
s%2Bd=28
substitute for d;
s%2B3s=28
highlight%28s=7%29
-
highlight%28d=21%29