Answer: - 7 1/2 feet
Explanation:
From the question, we are informed that a helicopter altitude changes by -28 1/8 ft in 3 3/4 s. The average change in the helicopters altitude each second will be gotten by dividing -28 1/8 by 3 3/4. This will be
= -28 1/8 ÷ 3 3/4
= -225/8 ÷ 15/4
= -225/8 × 4/15
= -15/2
= -7 1/2
The average change in the altitude each second is - 7 1/2 feet