Answer:
18 1/2 or 37/2
Step-by-step explanation:
To calculate the average of something, we add the numbers and divide by the count of those numbers. In this case, we have this as the sum of the numbers:
9 × 20 + 4 × 19 + 3 × 18 + 5 × 17 + 12
And the number of students as the count:
9 + 4 + 3 + 5 + 1
Now to calculate that out:
(9 × 20 + 4 × 19 + 3 × 18 + 5 × 17 + 12)/(9 + 4 + 3 + 5 + 1) ⇒
(180+76+54+85+12)/(9+4+3+5+1) ⇒
407/22 ⇒
37/2⇒
18 1/2
What I do is to add up the hundreds and tens in my mind first:
130 + 90 + 160 = 380
and then add the small change:
7.50 + 2.50 + 2.50 = 12.50
and add it back to the first amount
392.50
Answer:
A: -2 + 3i
B: -1 + -1i
C: 3 + -4i
D: 4 + 1i
I got all of these correct on Edgenuity.
Hope this helps :)
