SOLUTION: Trying to help myself and my 11 yr old daughter understand these word problems. Joseph, Brian, and Kyle spent $1,189 to buy a pc for their dad. Brian paid $148 more than Joe. Joe

Algebra ->  Customizable Word Problem Solvers  -> Finance -> SOLUTION: Trying to help myself and my 11 yr old daughter understand these word problems. Joseph, Brian, and Kyle spent $1,189 to buy a pc for their dad. Brian paid $148 more than Joe. Joe       Log On

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Question 697716: Trying to help myself and my 11 yr old daughter understand these word problems.
Joseph, Brian, and Kyle spent $1,189 to buy a pc for their dad. Brian paid $148 more than Joe. Joe paid $399 less than Kyle. How much did Brian pay? Your help will be greatly appreciated...

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
I always assign letters to the unknowns fight away
Let +a+ = amount in dollars that Joseph paid
Let +b+ = amount in dollars that Brian paid
Let +c+ = amount in dollars that Kyle paid
--------------------------------------
given:
(1) +a+%2B+b+%2B+c+=+1189+
(2) +b+=+a+%2B+148+
(3) +a+=+c+-+399+
-----------------
Substitute (2) into (1)
(1) +a+%2B+a+%2B+148+%2B+c+=+1189+
and
(3) +a+=+c+-+399+
(3) +c+=+a+%2B+399+
Substitute (3) into (1)
(1) +a+%2B+a+%2B+148+%2B+a+%2B+399+=+1189+
(1) +3a+=+1189+-+399+-+148+
(1) +3a+=+642+
(1) +a+=+214+
and, since
(2) +b+=+a+%2B+148+
(2) +b+=+214+%2B+148+
(2) +b+=+362+
and
(3) +c+=+a+%2B+399+
(3) +c+=+214+%2B+399+
(3) +c+=+613+
Brian paid $362
check:
(1) +a+%2B+b+%2B+c+=+1189+
(1) +214+%2B+362+%2B+613+=+1189+
(1) +1189+=+1189+
OK