Problema Solution
Rick has an older sister who is twice his ageˏ and a younger sister who is two years younger than him. If the product of the sisters ages is 70ˏ how old is Rick?
Answer provided by our tutors
let
r = the age of Rick, r>0
a = the age of the older sister, a>0
b = the age of the younger sister, b>0
Rick has an older sister who is twice his age
a = 2r
and a younger sister who is two years younger than him
b = r - 2
the product of the sisters ages is 70
a*b = 70
plug a = 2r and b = r - 2 into the last equations
2r*(r - 2) = 70
by solving we find
r = 7 years
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Rick is 7 years old.