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| Math Central | Quandaries & Queries |
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Question from sandhiya, a student: one group of people purchased 10 hotdogs and 5 soft drinks at a cost of $12.50.asecond group bought 7 hotdogs and 4 soft drinks at a cost of $9.00 find the cost of a single hot and a single soft drink.(using the row echelon form to solve) |
Hi Sandhiya,
I can help get you started.
First I am going to write the cost on cents rather than dollars so that I can work with integers. Let h be the cost of a hotdog in cents and s be the cost of a soft drink in cents. Then for the first group
10 h + 5 s = 1250
and for the second group
7 h + 4 s = 900.
The augmented matrix for this system of linear equations is then
The first thing I notice is that the first row has a common factor of 5 so multiply the first row by 1/5
Multiply the first row by -3 add add it to the second row
Can you complete the problem now?
Penny
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