word problems
posted by Bella on .
I can never do word problems...please help!!!!
Larry is 8 yrs older than his sister.In 3 yrs, hr will be twice as old as she will be then.how old is each now?

first use a random number for the sister's age. one, for example. so larry is 8 years older than that. 1+8=9, so larry is 9. in 3 years he will be 12, and his sister will be 4. 12 isnt twice as old as 4, so the sister is not 1. Try for yourself with different ages, like 2, 3, 4, 5, 6, and 7.

use x to represent his sisters age
his sister is x so larry is x+8
in 3 years the sister will be x+3 and larry will be 2x+3 because he is twice as old as her plus 3 years and then solve
x+8=2x+3
the answer is 5 his sister is 5 and he is 13