Problema Solution
kevin is 21 years older than his sister barbara. In 16 years, he will be twice as old as barbara. How old is each of them now?
Answer provided by our tutors
Let
k = Kevin's age now, k>0
b = Barbara's age now, b>0
Kevin is 21 years older than his sister Barbara:
k = b + 21
In 16 years, he will be twice as old as Barbara:
k + 16 = 2*(b + 16)
We have the following system:
k = b + 21
k + 16 = 2*(b + 16)
........
........
k = 26 years
b = 5 years
Kevin is 21 years old now.
Barbara is 5 years old now.