SOLUTION: Greg, Sam and Pedro went on shopping. Greg and Sam together spent a total of $17. Sam and Pedro spent $20. Greg and Pedro spent $21. How much did each person spent?

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Question 937273: Greg, Sam and Pedro went on shopping. Greg and Sam together spent a total of $17. Sam and Pedro spent $20. Greg and Pedro spent $21. How much did each person spent?



Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
(1) +g+%2Bs+=+17+
(2) +s+%2B+p+=+20+
(3) +g+%2B+p+=+21+
-----------------
Subtract (2) from (3)
(3) +g+%2B+p+=+21+
(2) +-s+-+p+=+-20+
-------------------
+g+-+s+=+1+
Add (1) and this result
+g+%2Bs+=+17+
+g+-+s+=+1+
--------------
+2g+=+18+
+g+=+9+
--------------
+g+-+s+=+1+
+9+-+s+=+1+
+s+=+8+
------------
(2) +s+%2B+p+=+20+
(2) +8+%2B+p+=+20+
(2) +p+=+12+
----------------
Sam spent $8
Greg spent $9
Pedro spent $12
----------------
check:
(1) +g+%2Bs+=+17+
(1) +9+%2B8+=+17+
+17+=+17+
OK
(2) +s+%2B+p+=+20+
(2) +8+%2B+12+=+20+
+20+=+20+
OK
(3) +g+%2B+p+=+21+
(3) +9+%2B+12+=+21+
+21+=+21+
OK