Answer:
120 coupons were used; yes, she should run the sale again
Explanation:
The total number of customers = 600
The percentage that used coupon = 20%
[tex]\begin{gathered} 20\%\text{ of 600} \\ =\frac{20}{100}\times600 \\ =120 \end{gathered}[/tex]Thus, 120 coupons were used.
Since more than 100 coupons were used, the manager should run the sale again.