[求助] 1个OG 12数学题

A store currently charges the same price for each towel that it sells. If the current price for each towel were increased by 1, 10 fewer of the towels could be bought for $120, excluding sales tax. What is the current price of each towel?

a.1
b.2
c.3
d.4
e.12

How can get out equation PN=120?(p=price,n=qty)

设原价为P时，卖出A个，

则原来总售价 PA

增长一块钱后，120块钱可以少买十个towel，那么可得：120/p  -120/p+1=10.那么化简得到：P^2+P-12=0.则P=3