A: 40
Let’s do this problem backwards.
TOTAL BOOKS RN: 36
1)
“Jill... then bought 16 more...”
36 - 16 = 20
After subtracting that amount, we would end up with half of the books Jill DID NOT sell.
2)
2 • 20 = 40
At this point, we multiplied amount of books she had after she sold half of her comic books by the reciprocal of 1/2
And now you have your answer!
Let the middle child be x
youngest child = x - 1
Oldest child = x + 1
(x - 1)^2 = 8(x + 1) + 4
x^2 - 2x + 1 = 8x + 8 + 4
x^2 - 10x - 11 = 0
(x - 11) * (x + 1) = 0
X = - 1 makes no sense. How can a middle child be - 1 years old?
x = 11
The youngest child is 10
The middle child is 11
The oldest child is 12
Check
=====
10^2 = 100
(8*12) + 4
96 + 4 = 100 So the results have been checked.
The proper way to set up this equation is: 15 > t / 5
V² + 16v + 64
v² + 8v + 8v + 64
v(v) + v(8) + 8(v) + 8(8)
v(v + 8) + 8(v + 8)
(v + 8)(v + 8)
(v + 8)²
