Question

Starting at sea level, a submarine descended at a constant rate to a depth of 3/4 mile relative to sea level in 4 minutes. What was the submarine's depth relative to sea level after the first minute?

Answer 1

The submarine descended at a depth of 3/4 of a mile in 4 minutes

and the motion was at a constant rate. Therefore we can make the following proportion:

(3/4)mi / 4 min = x mi / 1 min

where "x" represents the numer ofmiles descended in "1" (one) minute

So we solve for x by multiplying both sides of the equal sign by "1 min":

(3/4) / 4 mi = x

x = (3/16) mi

therefore, the depth relative to the sea level on the first minute was 3/16 miles (three sixteenths of a mile)