Question

The distance, d, in kilometres, travelled by a plane after t hours can be represented by d(t)=-4t³=40t²+500t, where t is greater than or equal to 0 and less than or equal to 10. How long does the plane take to fly 4088 km?

Answer 1

D(t) = -4t^3 + 40t^2 + 500t = 4088
4t^3 - 40t^2 - 500t + 4088 = 0
t = 7

Therefore, the plane has flown 4088 km 7 hours after it took off.