Question 113120: Helen's age next year will be three times Dan's age last year. Their present ages total 32. How old is each now?
Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website! This year Helen is h years old, and Dan is d years old. Helen's age next year then must be h + 1. And Dan's age last year must have been d - 1. The problem tells us:
Helen's age next year (h + 1) will be (=) 3 times Dan's age last year 3(d - 1).
So we can write:
Eq. 1)
We also know that their present ages, h and d, total 32, so we can write:
Eq. 2)
Start by solving Eq. 2) for one of the variables (doesn't matter which, I'll choose to solve for h)
, Adding -d to both sides.
Now we have an expression that represents h in terms of d that can be substituted into Eq. 1), thus:
Now, simplify and solve for d:
Distributive and Associative Properties
Adding -3d and -33 to both sides
Collecting terms
Divide both sides by -4, and now we know that this year, Dan is 9. Since the sum of their ages is 32, Helen must be 32 - 9 = 23.
Let's check the answer.
Helen's age next year will be 24. Dan's age last year was 8. 3 times 8 is 24. Furthermore, 9 + 23 = 32. So our numbers satisfy both of the conditions of the problem. Answer checks.
Hope that helps,
John
|
|
|