Final answer:
The greatest amount of friends Josh can invite so that everyone has the same amount of granola bars and fruit drinks is 18.
Step-by-step explanation:
Josh has 36 granola bars and 54 fruit drinks. To find the greatest number of friends he can invite while giving everyone an equal number of granola bars and fruit drinks, we need to find the greatest common divisor (GCD) of 36 and 54. The GCD of 36 and 54 is 18. Therefore, Josh can invite 18 friends so that each friend receives the same number of granola bars and fruit drinks.