<span>
<u><em>First, we need to get the amount of change:</em></u>The amount of change can either be an increase or a decrease.
It can be calculated as follows:
amount of change = </span>

<span>
If the amount of change is positive, then it is an increase
If the amount of change is negative, then it is a decrease
<u><em>Then, we need to convert this amount into a percentage:</em></u>Changing the amount into a percentage can simply be done by multiplying this amount by 100
This means that:
% of change = amount of change * 100
<u><em>Combining the two steps:</em></u>% of change = </span>

<span> * 100
<u>Examples:</u>The original price of a certain product was $10. It then became $12. Find the % of increase.
% of change = </span>

<span> = 20%
This means that the price increased by 20%
The temperature decreased from 25 degrees to 20 degrees. Find the percentage of decrease.
% of decrease = </span>

<span> = -20%
This means that the temperature decreased by 20%
Hope this helps :)</span>
Answer:
10
Step-by-step explanation:
(15 x 40) / (15+40)
solve inside the parenthesis:
600/60
divide:
10
1) 4 2/5 +1/5 = D)4 3/5
2)5 6/9- 1/3 = 5 1/3 or 16/3