During a storm, two teams of scientist leave a university at the same time in vans to search for tornadoes. The first team travels east at 20 miles per hour and the second travels west at 25 mph. If their radios have a range of up to 90 miles, how long will it be before they lose radio contact?

Their contact will end after 2 hours.

Step-by-step explanation:

Let east be positive and west be negative.

The first team travels east at 20 miles per hour.

Speed of first team = 20 mph

The second team travels west at 25 mph

Speed of second team = - 25 mph

Relative speed = 20 - (-25) = 45 mph

Range of radio = 90 miles

We need to find how long will it be before they lose radio contact.

Distance = Time x Speed

90 = Time x 45

Time = 2 hours

Their contact will end after 2 hours.