Answer:
The 40th customer was the first to get a free t-shirt and free water bottle
Explanation:
* Lets explain how to solve the problem
- A sporting goods store gave a free t-shirt to every 8th customer
- It gives free water bottle to every 10th customer
- We need to know which customer was the first to get a free t-shirt
and free water bottle
- The position of this person must be a number divisible by 8 and 10
∵ The first number divisible by 8 and 10 is 40
∴ The customer is the 40th
* Lets check that by this way:
- List the 8th positions and the 10th positions to find the common
position in the two conditions
# 8th , 16th , 24th , 32nd , 40th , 48th , ..................................................
# 10th , 20th , 30th , 40th , 50th , ......................................
∴ The 40th customer was the first to get a free t-shirt and free water bottle