Question

Kedar is comparing the costs of phone plans. For phone plan A, the cost is $15.00 to connect and then $0.02 per minute. For phone plan B, the cost is $4.69 to connect and then $0.08 per minute. For what usage does plan A cost the same as plan B? (Hint: Find total minutes and then convert to hours and minutes.)

3 h 2 min

2 h 42 min

3 h 12 min

2 h 52 min

Answer 1

The answer is (D): 2 h 52 min

Explanation:

write these equations separately as functions:

A(x)=15+0.02m

B(x)=4.69+0.08m

Since we want to find when they are equal, set them equal to each other:

15+0.02m=4.69+0.08m

simplifying this equation gives

10.31+0.02m=0.08m

subtract 0.02m from both sides

10.31=0.06m

divide both sides by 0.06

m=171.833 etc approximately equals 172 minutes

172 min/60=

2 hours and 52 min

Hope this helps!

Answer 2

2 h 52 min

Explanation:

Let m represent the number of minutes that will make the plans have equal cost. Equating the two plan costs, we have ...

15.00 + 0.02m = 4.69 + 0.08m

10.31 = 0.06 m . . . . . subtract 4.69+0.02m

10.31/0.06 = m = 171.8333... ≈ 172 . . . . minutes at equal cost

There are 60 minutes in an hour, so ...

172 minutes = 120 minutes + 52 minutes = 2 hours + 52 minutes

Plan A will cost the same as Plan B for 2 h 52 min of usage.