SOLUTION: Six years ago,Mac's age is 20 years less than twice Kim's age. If Kim is 3 years older than Mac's. Find their ages four years from now.

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Question 1185226: Six years ago,Mac's age is 20 years less than twice Kim's age. If Kim is 3 years older than Mac's. Find their ages four years from now.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
"Six years ago,... is,..."
No. Either drop the six years ago, or say "was".


This part: "Six years ago,Mac's age is 20 years less than twice Kim's age. "
seems to say how the first portion relates to Kim's age NOW.
m-6=-20%2B2k

IF Kim is 3 years older (NOW), then k-m=3

system%28m-6=2k-20%2Ck=m%2B3%29
-
m-6=2%28m%2B3%29-20
m-6=2m%2B6-20
-6-6%2B20=m
-12%2B20=m
m=8andk=11----------their ages now.

In four years, Mac and Kim, 12 and 15.




Maybe problem is really supposed to be this way:
=======================================================================
Six years ago, Mac's age was 20 years less than twice Kim's age. If Kim is 3 years older than Mac's,...
=======================================================================

m-6=-20%2B2%28k-6%29
m-6=-20%2B2k-12
m-6%2B20%2B12=2k
m%2B26=2k----------then substitute for k=m%2B3
m%2B26=2%28m%2B3%29
m%2B26=2m%2B6
m=20--------k=23

Their ages in four more years,
=============
Mac, 24
Kim, 27
=============

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Let x be Mac's age now
Then x+3 is Kim's age now (he is 3 years older than Mac)

Then

x-6 = Mac's age 6 years ago
x+3-6 = x-3 = Kim's age 6 years ago

Mac's age 6 years ago was 20 less than twice Kim's age (then):

x-6+=+2%28x-3%29-20
x-6+=+2x-6-20
20+=+x

Their current ages are x=20 and x+3=23.

ANSWER: Their ages 4 years from now will be 20+4=24 and 23+4=27