SOLUTION: At M & P’s Deli, two pastrami sandwiches and five sodas cost $12.65, while three pastrami sandwiches and two sodas also cost $12.65. How many dollars would seven pastrami sandwic

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Question 1189023: At M & P’s Deli, two pastrami sandwiches and five sodas cost $12.65, while three pastrami sandwiches and two sodas also cost $12.65. How many dollars would seven pastrami sandwiches and twelve sodas cost?
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52879) About Me  (Show Source):
You can put this solution on YOUR website!
.
At M & P’s Deli, two pastrami sandwiches and five sodas cost $12.65,
while three pastrami sandwiches and two sodas also cost $12.65.
How many dollars would seven pastrami sandwiches and twelve sodas cost?
~~~~~~~~~~~~~~

Notice that twice first purchase PLUS the second purchase is, comparing the items, EXACTLY the third purchase.


THEREFORE, the cost of the third purchase is EXACTLY twice the cost of the first purchase PLUS the cost 
of the second purchase.


So, the cost of the third purchase is  2*12.65 + 12.65 = 37.95 dollars.


ANSWER.  7 pastrami sandwiches and 12 sodas cost $37.95.

Solved.

----------------

Notice that there is no need to solve equations
to get the answer,  and I did not solve them.



Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
p for price of pastrami sandwich
d for price of one soda drink

system%282p%2B5d=12.65%2C3p%2B2d=12.65%29

If multiply first equation by 2, and THEN add the two equations:
system%284p%2B10d=25.3%2C3p%2B2d=12.65%29

7p%2B12d=highlight%2837.95%29 which is exactly what the question asks.