Question

A submarine descended 3/5 of a kilometer in 1/5 of an hour. What was the submarine’s rate of descent in kilometers per hour?

Answer 1

3 km per hour

Explanation:

You can deduct the answer instinctively since both the distance and the time of the descent are expressed in /5... so you can just get rid of the '/5' in both instances to get the result: 3 kilometers in 1 hour.

But you can also find it easily using the cross-multiplication system:

`(3)/(5) km  =  (1)/(5)  hour`

Then you multiply each side by 5 to get

3 km = 1 hour

Thus the rate of descent is of 3 km per hour.

Answer 2

3 kilometer per hour

Explanation:

We are given that a submarine descended 3/5 of a kilometer in 1/5 of an hour and we are to find the submarine's rate of descent in kilometers per hour.

`(3)/(5) kilometer = 0.6 kilometer`

`(1)/(5) hour = 0.2 hour`

Using the ratio method to find the rate of descent:

`(0.6km)/(x) =(0.2hour)/(1 hour)`

`x = (0.6)/(0.2)`

`x=3`

Therefore, the rate of descent of submarine is 3 kilometer per hour.