$88
Explanation:
Adults $12x5 = 60
Child $7x 4=28
60+28=88
B=160+ 5c
b= 304- 3c
160+5c=304-3c
+3c +3c
160+8c=304
-160 -160
8c= 144
c=18
An = a1 + (n-1)*d
n = term to find = 30
a1 = first term = 20
d = common difference = 2
a30 = 20 + (30 - 1) * 2
a30 = 20 + 29 * 2
a30 = 20 + 58
a30 = 78
sn = (n (a1 + a30)) / 2
s30 = (30(20 + 78) / 2
s30 = (30(98) / 2
s30 = 2940/2
s30 = 1470 <===
Each one is multiplied by -2...
PROOF
-5 * 10 = -20
-20 * -2 = 40
And so on.
So we need two more numbers so do 40 * -2...
40 * -2 = -80
And then...
-80 * -2 = 160
So the first 6 numbers are...
-5, 10, -20, 40, -80, 160.
We need to find the SUM, which is all the numbers added together.
-5 + 10 - 20 + 40 - 80 + 160 = 105
105 is your answer.
By flipping the fraction of -3/7, you will get the fraction of -7/3 or - 2 1/3.
Therefore, the reciprocal of -3/7 is - 2 1/3.
Hope this helps!
