The question above can be answered by using the equation below,
PΔt = 1/2 (mv²)
From the first case, we solve the power.
P(3.2s) = 0.5(1500)(55² - 35²)
This gives us a value of P which is 421875.
Using this same power to solve for t in the second scenario,
421875 *t = 0.5(1500)(100²-55²)
The value of t is 12.4 s.