Answer:
26
Step-by-step explanation:
Since x is counted in hundreds, x=600/100.
x=6
6x-10
When you substitue,
6*6-10
36-10
26
you get 26.
David's score on his fifth test would be an 87. If you add up all the scores from his first to his fourth test, it would 363. However, since there are five tests, in order to get a 90 percent, the sum of all five test scores would be 450. 450 - 363 = 87.