SOLUTION: Dad's age is equal to the sum of Laura's, Jeri's and Theresa's ages. If Jeri is 4 years older than Theresa and 3 years younger than Laura, and Dad's age is 38, how old is each daug

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Question 175799: Dad's age is equal to the sum of Laura's, Jeri's and Theresa's ages. If Jeri is 4 years older than Theresa and 3 years younger than Laura, and Dad's age is 38, how old is each daughter?
Found 2 solutions by EMStelley, josmiceli:
Answer by EMStelley(208) (Show Source):
You can put this solution on YOUR website!
Let's start by declaring variables
D - dad's age
L - laura's age
J - jeri's age
T - theresa's age
The first statement tells us that D = L + J + T
Jeri being 4 years older than Theresa gives us
J = T + 4
Jeri being 3 years younger than Laura gives us
J = L - 3
So notice that the common variable in these two equations is J. So if we can represent every girls age in terms of Jeri's, we will be down to one variable. So
T = J - 4
L = J + 3
Now, we can rewrite the original equation using only J's
38 = (J + 3) + J + (J - 4)
38 = 3J - 1
39 = 3J
13 = J
So Jeri is 13, and thus Theresa is 9 and Laura is 16.

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
Let = Laula's age
Let = Jeri's age
Let = Theresa's age
Let = Dad's age
----------
Given:
(1)
(2)
(3)
(4)
-----------
From (3)

From (4)

Now substitute these into (2)
(2)
(2)

and, since

also,

Laura is 16, Jeri is 13, and Theresa is 9
check:
(2)

OK