Answer:
Gabe worked for 6 2/3 hours and Paula worked for 4 hours.
Explanation:
It is given that,
Diana worked on her science project for 5 1/3 hours.
Gabe worked on his science project 1 1/4 times as long as Diana.
Paula worked on her science project 3/4 as long as Diana.
Solution,
ATQ,
Gabe worked for :

Pauls worked for :

Hence, Gabe worked for 6 2/3 hours and Paula worked for 4 hours.