During a promotional event a sporting goods store gave a free t-shirt to every 8th customer and free water bottle yo every 10th customer which customer was the first to get a free t-shirt and free water bottle

The 40th customer was the first to get a free t-shirt and free water bottle

Step-by-step 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