It's the sum of the three masses:

88+ 92+ 82+ 94 + x
———————————— = 90
5
x= 5th test
The answer is D:) I hope this helped.. And download the app Connects it helps with math problems and people actually help and solve them
3,345 divided by 18 is 185.8333....The three goes on forever.
Steps:
Does 18 go into 3? No
Does 18 go into 33? Yes
How many times? 1
33-18= 15, and then you would bring down and keep doing what I did. Hope this helped!