You need to set it up as a fraction and make the fractions equal each other.
2/3 (2 of their books for 3 of yours)
x/18 (x amount of their books for 18 of yours)
(2/3)=(x/18)
multiply both sides by 18
and you get
36/3 which reduces to 12
so your answer is 12
Step-by-step explanation:

Answer: 16500(.65)^3 =4531.31
Step-by-step explanation:
Answer:
Dont think eh multiplied both sides by 4. That would be the first step.
Step-by-step explanation:
1/4(x+12)=2
multiply both sides by 4
x+12=8
move the 8 to the right side of the equation and change its sign
x=8-12
calculate
x= -4
$45 ÷ 5 = 9 (T-shirts sold so far)
$150 ÷ 5 = 30 (t-shirts they want to sell in order to have a goal of $150)
30-9= 21 more t-shirts
Ans: 21