Solve the problem involving distance, rate, and time. See Example.EXAMPLE Finding Distance...

Solve the problem involving distance, rate, and time. See Example.

EXAMPLE Finding Distance, Rate, or Time

Solve each problem using a form of the distance formula.

(a) The speed of sound is 1088 ft per sec at sea level at 32°F. Find the distance sound travels in 5 sec under these conditions.

We must find distance, given rate and time, using d = rt (or rt = d).

(b) The winner of the first Indianapolis 500 race (in 1911) was Ray Harroun, driving a Marmon Wasp at an average rate (speed) of 74.59 mph. (Source: Universal Almanac.) How long did it take him to complete the 500 mi?

We must find time, given rate and distance, using .

To convert 0.70 hr to minutes, we multiply by 60 to get 0.70(60) = 42. It took Harroun about 6 hr, 42 min, to complete the race.

(c) At the 2008 Olympic Games, Australian swimmer Leisel Jones set an Olympic record of 65.17 sec in the women’s 100-m breaststroke swimming event. (Source: World Almanac and Book of Facts.) Find her rate.

We must find rate, given distance and time, using .

Suppose that an automobile averages 45 mph and travels for 30 min. Is the distance traveled 45 × 30 = 1350 mi? If not, explain why not, and give the correct distance.