4 cups per quarter
4 x 7 = 28
28 kids can have a cup of hot chocolate.
The average rate of change is defined as the slope of the secant line and is given by the formula
[f(x+h)-f(x)]/h; where h=x₂-x₁.
[f(w+h)-f(w)]/h
= [0.11(w+h)² - 0.2(w+h) + 1.33 - 0.11w² + 0.2w - 1.33] / h
= [0.11w²+0.22wh+0.11h²-0.2w-0.2h-0.11w²+0.2w] / h
= [0.22wh + 0.11h² - 0.2h] / h
= 0.22w + 0.11 h - 0.2
w₂ = 700 g and w₁ = 400 g
0.22(400) + 0.11 (700-400) - 0.2 = 120.8 hectares/g
