15 I may be wrong but If I am please provide more information.
Answer:
-5n + 8
Step-by-step explanation:
<u>1. What is the difference?</u>
The sequence goes down by 5. This means that the formula will have -5n in it.
<u>2. Work out the term before the first term.</u>
The first term is 3, and we know that the sequence goes up by 5. So, to get the term before 3 we would add 5.
3 + 5 = 8 Remember, this is positive 8. (+8)
<u>3. Put that term at the end of the equation. </u>
We have -5n already and we just worked out the term before the first one which is positive 8 - so put that at the end of the equation.
-5n + 8 This is our answer!
Just to prove it works:
<em>Substitute: n = term</em>
Lets see if we can get the 3rd term which is -7. (n = 3)
-5(3) + 8
-15 + 8 = -7
See, it works!
Multiply your total by your percentage
90 * .80 = 72
72 is the number of questions she answered correctly
