The answer is C.1/2 because there is only possible numbers are 3,5,6.
<u>Answer:</u>
96
<u>Step-by-step explanation:</u>
Let's assume that the marks needed in the next exam is
. Then if the average becomes 90,

Now we can simply solve for
:
⇒ 
⇒
[Multiplying both sides by 4]
⇒
[Subtracting 264 from both sides]
⇒ 
Therefore, you need to score 96 in your next exam to have an average of 90 on the four exams.
Answer:
Step-by-step explanation:
- (y+9) = 10
Multiply through by -1 gives us
y+9 = -10
Subtract 9 from both sides
y = -19
That's your answer.
If you work it through it satisfies the equation.
That is:
- (-19 +9) = 10
-(-10) = 10
10 = 10
Boo ya!