Dwayne answered 80% of the questions on a quiz correctly.If he answered 40 questions correctly what was the total number of ques
2 answers:
You might be interested in
We are given:
Our goal in solving for any variable, in this case is x, we need to isolate x on one side of the variable. Let's start by subtracting 7x from both sides, which will cancel the +7x on the right side. We are then left with:
Now, we want to move that +10 to the other side so our x is all by itself. Let's subtract 10 from both sides, which will cancel the +10 on the right leaving us with:
Since we cannot have a coefficient when solving for x, we need to divide both sides by -3.
When we divide, our answer is:
Answer:
-675
Step-by-step explanation:
The sum can be broken into parts that you know. Here, one of those parts is the sum of numbers 1 to n. That sum is given by n(n+1)/2.
__
Another way to do this is to realize the sequence of numbers is an arithmetic sequence with a first term of 65 and a last term of 67-2·75 = -83.
The sum of an arithmetic sequence is found by multiplying the number of terms by their average value. Their average value is the average of the first and last terms.
The average value of those 75 terms is (65 +(-83))/2 = -9, so their sum is ...
75(-9) = -675