SOLUTION: Billy went to the store and bought 5 pants and 3 shirts for $145. He went again the next day and bought 2 pants and 5 shirts for $135. What is the cost of a pants and a shirt?

Algebra ->  Inverses -> SOLUTION: Billy went to the store and bought 5 pants and 3 shirts for $145. He went again the next day and bought 2 pants and 5 shirts for $135. What is the cost of a pants and a shirt?      Log On


   

Question 1060704: Billy went to the store and bought 5 pants and 3 shirts for $145. He went again the
next day and bought 2 pants and 5 shirts for $135. What is the cost of a pants and a
shirt?
Found 2 solutions by addingup, Alan3354:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
5p+3s = 145 multiply all times 5
2p+5s = 135 multiply all times -3
---------------------
New equations (after multiplication. Add them together:
25p+15s = 725
+
-6p-15s = -405
19p-0s = 320
rewrite:
19p = 320 divide both sides by 19
p = 16.84 is the price of one pair of pants.
:
Now for the shirts:
5p+3s = 145 multiply all times 2
2p+5s = 135 multiply all times -5
---------------------
New equations (after multiplication. Add them together:
10p+6s = 290
+
-10p-25s = -675
0p-19s = -385
rewrite
-19s = -385 divide both sides by -19, and remember -/- = +
s = 20.26
-----------
Or you can take a shortcut for the shirts:
145-(16.84*5))/3 = 20.26
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
Check - Put these numbers in the original equations (I'll do one, you can do the other if you want):
5p+3s = 145
5(16.84)+3(20.26) = 145
84.20+60.78 = 144.98 = 145 there is a difference of 0.02 due to the rounding of decimals.
:
John


Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Billy went to the store and bought 5 pants and 3 shirts for $145. He went again the
next day and bought 2 pants and 5 shirts for $135. What is the cost of a pants and a
shirt?
---------------------
5p + 3s = 145
2p + 5s = 135
----
Can you solve those?