The amount of drinks is a linear function of the number of drinks. The maximum amount that can be purchased is 100 soft drinks.
Let
amount of drinks
number of drinks
For drinks not more than 50
For drinks more than 50.
For a purchase of $85, it means that:
So, we solve for x in both equations.
Collect like terms
Divide through by 0.8
--- approximated
Collect like terms
Divide by 0.7
By comparing both values:
Hence, the maximum amount that can be purchased is 100
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