Question 830654
Let L = Loren's age and P = Ping's age
We're told the following:
L = 3/4P
L-4 = 1/2(P+4)
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Substitute the value for L
(3/4P)-4 = 1/2(P+4)
Distribute
3/4P - 4 = 1/2P + 2
Add 4 to each side
3/4P = 1/2P + 6
Subtract 1/2P (same as 2/4P) from each side
1/4P = 6
Multiply each side by 4
P = 6*4
P = 24
If Ping is 24 and Loren is 3/4 his age, then Loren is 18.<<--
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Let's put the ages into the original problem to see if they work.
"four years ago, she was 4 years more than 1/2 as old as Ping. "
Using the values we found, 4 years ago, Loren would have been 14.
Is that 4 years more than 1/2 of Ping's age?  If he is 24 now, 4 years ago he would have been 20.  1/2 of that is 10.  4+10 is indeed 14.