Final answer:
To calculate the time taken for a motorboat moving at 40 ft/s to cover 160 feet, we use the formula time = distance/speed, which gives us 4 seconds.
Step-by-step explanation:
The speed of a motorboat is given as 40 ft/s. We are asked to find the time taken for the boat to cover a distance of 160 feet. To find the time, we can use the formula time = distance / speed. Plugging in the values provided:
time = 160 feet / 40 ft/s = 4 seconds.
Therefore, the correct answer is (a) 4 seconds.