To calculate the average you add up all the scores and divide by the number of scores (5)
add all the current test scores and allow X to be the unknown score:
92+80+88+93+X: or 353 + X
set up equation:
(353+X)
______ = 90
5
Multiply both side of the equation by 5 to clear the fraction resulting in:
353+X=450
Subtract 353 from both sides of the equation:
x = 97
So the test score needed to get a 90 average is 97.
Answer:
X=56/9
Step-by-step explanation:
7x+2(x-5)46
7x+2x-10=46
9x-10=46
9x=46+10
9x=56
Compute the unit rates.
Tank A:
(5/8 gal) / (1/2 min) = 10/8 gal/min = 5/4 gal/min = 1.25 gal/min
Tank B:
(3/5 gal) / (1/4 min) = 12/5 gal/min = 2.2 gal/min
So tank B is filling faster.