Question 174622
A plum and a pineapple cost the same as three peaches. Two plums cost the same as a peach. How many plums cost the same as a pineapple?
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plum + pine = 3*peach
2*plum = peach
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Substitute to get:
plum + pine = 3*2plum
plum + pine = 6plum 
pine = 5*plums
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Cheers,
Stan H.