Answer:

Step-by-step explanation:
1. Approach
To solve this problem, one wants to find the price of a product after its discount has been applied. The discount is 20% off, so the new price of the item is 80% of its original price (percent is out of 100 so if a an item is 20% off, it is 100 - 20 = 80; 80% the original price). To calculate the percent cost, one would divide the percent value by 100, and then multiply it by the price of the item.
2. Solving
The price of the new item is 80% of the price of the original item. To calculate the percent cost, cent, one would divide the percent value by 100, and then multiply it by the price of the item.
Therefore, the equation that will be formed is,

Substitute,

Simplify,

Answer:
Mike had 72 stamps
Ken had 120 stamps
Step-by-step explanation:
Given




Required
Find K and M
Make K the subject in: 

Substitute
in 
![\frac{1}{5} * [3 * ( M - 24) - 24] = \frac{1}{3} * M](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7D%20%2A%20%5B3%20%2A%20%28%20M%20-%2024%29%20-%2024%5D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%20%2A%20M)
Open brackets
![\frac{1}{5} * [3M - 72 - 24] = \frac{1}{3} * M](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7D%20%2A%20%5B3M%20-%2072%20-%2024%5D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%20%2A%20M)
![\frac{1}{5} * [3M -96] = \frac{1}{3} * M](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7D%20%2A%20%5B3M%20-96%5D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%20%2A%20M)
Multiply both sides by 15
![3* [3M -96] = 5 * M](https://tex.z-dn.net/?f=3%2A%20%5B3M%20-96%5D%20%3D%205%20%2A%20M)

Collect like terms


Divide both sides by 4

Substitute
in 



I think the answer is A
Hope it helps :-)
The answer would be 3, 2-2+3, I’m pretty sure.
29 tenths
29 1/10
29/10 = 2.9
2.9 is your answer
hope this helps