We can use implicit differentition to determine the second derivative of y in terms of x. In this case, the first derivative is 2x dx - 2y dy = 0. The second derivative is 2 d2x - 2 d2y = 0. Hence d2y/d2x is equal to 1.
Michelle: x Ian: 5x Joe: 7x Michelle + Ian + Joe = 208 berries x + 5x + 7x = 208 Combine like terms: 13x = 208 Divide both sides by 13: x = 16 Joe = 7x = 7*16=112 Joe picked 112 berries
