[問題] GWD18-23

[little8]

Q23:
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

I choose A, but the answer is B

thanks for your response

[kwtluck]

2x*(0.75-0.3)> 13
x>14.4=>所以x=15

[balanana]

2x*(0.75-0.3)> 13
x>1.4=>所以x=15

X>14.4

[kwtluck]

謝謝你的指正

[little8]

謝謝
我懂了