Three more than a certain number is
18 less than twice the number.
What is the number?

Then number is 21

Step-by-step explanation:

a+3=2a-18

Collect like terms we have

2a-a=3+18

a=21

(2,20) means that the 2 is 2 hours and 20 is 20$. so there both 20$ for 2 hours only the same price. like it says. so, the dunk tank and the bounce house are the same price (20$) for the same amount of time (2 hours).

hope i