Question 1050002: Jerry is four times as old as Laura. In 20 years he will be twice as old as Laura. How old are Jerry and Laura? Answer by ikleyn(52781) (Show Source):
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Jerry is four times as old as Laura. In 20 years he will be twice as old as Laura. How old are Jerry and Laura?
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J = 4L. (1)
In 20 years:
J+20 = 2(L+20). (2)
Substitute (1) into (2). You ill get
4L + 20 = 2(L+20), or
4L + 20 = 2L + 40,
4L - 2L = 40 - 20,
2L = 20 ---> L = 10. Laura is 10 years now.
J = 4L = 4*10 = 40. Jerry is 40 years now.
Answer. Laura is 10 years now. Jerry is 40 years now.
Please check it yourself.
