Answer:
Student B
Explanation:
You want to know the student who raised the least amount of money walking 7 miles if the money raised by each student is ...
- A: y = 13x; y dollars for x miles
- B: $36 for 3 miles
- C: $52 for 4 miles, $65 for 5 miles
Dollars per mile
The amounts raised for 7 miles can be found either by computing the actual amount for 7 miles, or by comparing the rate in terms of dollars per mile.
A
The equation y = 13x tells you the amount raised increases by $13 for each increase in distance of 1 mile. Student A raises $13 per mile. For 7 miles, they will raise $13·7 = $91.
B
The rate at which student B is raising money is found by dividing dollars by miles:
$36/(3 miles) = $12/mile
Student B raises $12 per mile. For 7 miles, they will raise $12·7 = $84.
C
Student C raises $52/(4 miles) = $13/mile. They will raise the same amount of money for 7 miles that student A does: $91 for 7 miles.
The student raising the least amount of money after walking 7 miles is Student B.
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Additional comment
We note that Student C's rate of $65 for 5 miles is still $65/(5 mi) = $13/mi, the same rate as for 4 miles.
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