Question

After a robot vacuum is fully charged, it can run for 15 minutes. It can vacuum 1/2 square foot every second. Can a fully charged robot clean a room that is 400 square feet without recharging?

Answer 1

The robot can clean the room without recharging.

Explanation:

Given:

After a robot vacuum is fully charged, it can run for
`15` minutes.

The robot cleans
`(1)/(2)` square foot every second.

To find: If the charged robot can clean a room that is
`400` square feet without recharging.

Solution:

Area cleaned by the robot in
`1` second
`=(1)/(2)` square foot.

We know that,
`1` minute
`=60` seconds.

So,
`15` minutes
`=15* 60=900` seconds.

Now, area cleaned by the robot in
`900` seconds
`=(1)/(2) * 900=450` square feet.

The area to be cleaned is
`400` square feet.

Hence, the robot can clean the room without recharging.