Mark now is x^2
at some time in the future, Mark is 10x
so the change in time is 10x - x^2
Peter's age will change by that same number
so Peter's age will be x + 10x-x^2
= 11x - x^2
but 3x = 11x- x^2
x^2 - 8x = 0
x(x-8) = 0
x = 0 , not likely
or
x = 8
So Mark is now 64 and Peter is now 8
check:
When Mark is 80, sixteen years from now, Peter will be 16+8 or 24 years, which is 3(8)
All is good.
Last one
At present, Mark's age is x^2 years and Peter's age is x years. When mark is 10x years, Peter will be 3x years. What are their present ages?
Question is kind of confusing to me, so again i just need help forming the equation. Thanks.
1 answer