Answer:
- 2 trees ($200 from either service)
- c=100+50t
- c=80+60t
Step-by-step explanation:
It can work well to solve problems like this by considering how many times the difference in per-tree costs it takes to make up the difference in one-time costs.
Here the difference of one-time costs is $20, and the difference in per-tree costs is $10, so it takes the pruning of 2 trees for the per-tree cost difference to equal the one-time cost difference (2×10 = 20).
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The cost equations are ...
cost = (one-time cost) + (per tree cost) × (number of trees)
c = 100 + 50t . . . . . company A
c = 80 + 60t . . . . . . company B
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If you use these equations to solve the problem, you want to find t such that the two costs are equal:
100 +50t = 80 +60t
(100 -80) = t(60 -50) . . . . . . . subtract 80+50t, factor out t
(100 -80)/(60 -50) = t . . . . . . . looks a lot like the verbal description above
The difference in fixed price divided by the difference in per-tree cost) is the number of trees required to make costs equal.
Answer:
Step-by-step explanation:
For one, there can only be two variables, for two, two variables cannot be multiplied together. For example, xy + 2z= 4 is not linear.
