Question

Need help on 8,9,10,11 and 12

Answer 1

8) 12 is 30% of some number, which we'll call x. We can write the percent as a decimal and solve for x
$0.3x=12 \\ \\ x = 40$.
The answer is 40.

9) 45% of 20 is $0.45(20)=9$.

The answer is 9.

10) 18 is $(18/30 = 60)$% of 30.

The answer is 60%.

11) 56 is 80% of some number x. We write 
$0.8x=56 \\ \\ x = 70$.

The answer is 70.

12) If the total cost on an item that costs $4.00 is $4.32, then the tax is 32¢. We want to find the percent of the total 4 that is .32. $\frac{0.32}{4} = 0.08=8$%.

The answer is 8%.