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Question 1032436: Tasha bought salads at $2.75 each and cartons of milk at $.80 each. The total cost was $16.15. How many of each did Tasha buy?
I will be using the variable s for the number of salads and m for the cartons of milk. My equation is 2.75s + .80m = 16.15.
I would like some help on how to solve the problem using this equation.
Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Tasha bought salads at $2.75 each and cartons of milk at $.80 each. The total cost was $16.15. How many of each did Tasha buy?
I will be using the variable s for the number of salads and m for the cartons of milk. My equation is 2.75s + .80m = 16.15.
I would like some help on how to solve the problem using this equation.
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You need another equation statement.
The usual one is "total number of items is 'n'
Then you would have two equations::
Quantity Eq::s + m = n
Value Eq:: 2.75s + 0.80m = 16.15
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Cheers,
Stan H.
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Answer by ikleyn(52794)  (Show Source):
You can put this solution on YOUR website! .
Tasha bought salads at $2.75 each and cartons of milk at $.80 each. The total cost was $16.15. How many of each did Tasha buy?
I will be using the variable s for the number of salads and m for the cartons of milk. My equation is 2.75s + .80m = 16.15.
I would like some help on how to solve the problem using this equation.
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Your equation is correct, and the problem has a unique solution.
It may seems to be strange: one equation, two unknowns and the unique solution?
Nevertheless, it is true.
The key to resolve this mystery is the fact that you are looking for solutions among integer s and m only.
It is very strong restriction, which replaces the second equation in this case.
So, solve it in this way.
Take s = 1. Calculate 16.75 - s*2.75 = 13.40. Divide it by 0.8. Will you get the integer quotient? - No, in this case.
Take s = 2. Calculate 16.75 - s*2.75 = 10.65. Divide it by 0.8. Will you get the integer quotient? - No, in this case.
Take s = 3. Calculate 16.75 - s*2.75 = 7.90. Divide it by 0.8. Will you get the integer quotient? - No, in this case.
. . . . .
Check s = 5. !!!!! You will get the integer quotient m = 3.
So, s = 5 and m = 3 is your solution.
You have managed to find the unique solution of the problem described by one equation with two unknowns.
It became possible only because you were looking for integer solutions.
Congratulations !
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