Problem Solving

The toll for crossing a certain bridge is $0.75 each crossing. Drivers who frequently use the bridge may instead purchase a sticker each month for $13.00 and then pay only $0.30 each crossing during that month. If a particular driver will cross the bridge twice on each of x days next month and will not cross the bridge on any other day, what is the least value of x for which this driver can save money by using the sticker?

A. 14
B. 15
C. 16
D. 28
E. 29

thanks!

The stimulus says that the driver will pass twice per day, so without the plan the cost will be (0.75 + 0.75)x and with the plan 13 + (0.3 + 0.3)x.

The question asks you to find the value of x for which the driver will save money by using the plan

13 + 0.6x < 1.5x ---> 13 < 0.9x --->x > 13/0.9 ---> x > 14.444

so x=15 making B the correct answer.

great, your explanation seems to be easier than the official one