Answer:
see below (I hope this helps!)
Step-by-step explanation:
p² = 4x² * (q(1 + r² / y²) / S)
p²S = 4x² * q(1 + r² / y²)
p²S / 4x²q = 1 + (r² / y²)
p²S / 4x²q - 1 = r² / y²
y² = r² / (p²S / 4x²q - 1)
y = √( r² / (p²S / 4x²q - 1) = √(r²4x²q / (p²S - 4x²q))
The mean score is 87
79x2=158
158-71=87
13/60 was left of the ice cream.
4/5 was left after the first, which can also be written as 16/20. 16/20 - 1/4 (also written as 5/20), which leaves 11/20 which can also be written as 33/60. 33/60 - 1/3 (also written as 20/60) which leaves 13/60 left.
babylonia asyria and south merica this
D=32.09
160.01-127.92=32.09
to 
