Question 261101
The number of calories in a piece of pie is 20 less than three times the number of calories in a scoop of ice cream. 
The pie and ice cream together have 500 calories. How many calories are in each?
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Equations:
Quantity Equation:  p + i = 500
Quantity Equation:  p = 3i -20
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Substitute for "p" and solve for "i":
3i-20 + i = 500
4i = 520
i = 130 (# of calories in ice cream)
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Since p+i = 500, p = 500-130 = 370 (# of calories in a piece of pie)
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Cheers,
Stan H.