Answer: 56.4102564% decrease
Explanation: First determine whether the number is increasing or decreasing. Since it changes from 39 to 17, it's going down so it's decreasing.
Now to find the percent decrease,
we divide the amount of change by the original number.
The amount of change is the difference between the two numbers
which in this case is 39 - 17 and the original number is 39.

39 - 17 is 22 so we're left with
which gives us 56.4102564
Remember however that our problem is asking for a <em>percent</em>, not a decimal. So we need to write 56.4102564 as a percent by moving the decimal point 2 places to the right to get 56.4102564.
So when a number changes from 39 to 17, it has decreased by 56.4102564%.
Answer:
C is the answer
Step-by-step explanation:
We calculate the floor area of the kitchen:
A = (22) * (16)
A = 352 feet ^ 2
We consider the following conversion:
1 foot = 12 inches.
Applying the conversion we have:
A = 352 * (12/1) ^ 2
A = 50688 in ^ 2
We calculate the area of each tile:
A = (16) * (16)
A = 256 in ^ 2
Then, the number of tiles is given by:
N = (50688) / (256)
N = 198
Answer:
He needs to buy 198 tiles
To reverse a percentage decrease you divide it by the decrease (+ 100%)
For example we will pick the number, 100, which is decreased by 15% to 85.
To make 85 back to 100 we divide it by the decrease (1-0.15):
85 / 0.85 = 100
To find out how much 85 increased to get back to 100, we do:
15 / 85 = 0.1765 = %17.65
15 is the reduction/difference, and 85 is the with reduction total.
Because percentages stay the same, this is applicable to any numbers, from this, we know that whenever something is reduced by 15% - when restored to it's original is increased by %17.65
The answer is %17.65

The fixed cost is $150, while the per-student cost is $6.