A flare is launched from a boat. The height, h, in meters, of the flare above the water is approximately modelled by the function h(t) = -15t2 + 150t, where t is the number of seconds after the flare is launched. How many seconds will it take for the flare to return to the water?

Answer 1

To find when the flare returns to the water, we need to find when the height above the water is equal to zero.

Setting h(t) = 0, we get:
-15t^2 + 150t = 0

Factoring out a t, we get:
t(-15t + 150) = 0

Setting each factor to zero:
t = 0 and -15t + 150 = 0
-15t = -150
t = 10

So, the flare will return to the water after 10 seconds.