<PRE><B>Question 881210</B>
F = 4D
F-5 = 7(D-5)
Distribute
F-5 = 7D-35
Substitute the value of F from the first equation into the second
4D-5 = 7D-35
Subtract 4D from each side
-5 = 3D - 35
Add 35 to each side
30 = 3D
Divide each side by 3
D = 10
.
If the daughter is 10, the father is 40.
Five years ago, she was 5 and he was 35 (7 times her age)
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