Im in a car at 50mi/hr. I enter a tunnel and hold my breath for 8 seconds. How many feet long was the tunnel? (1mi=5280ft)

Question

Help please..this has been hard all u need to know is in the question.

Answer 1

I would approach this by finding out how many feet a car travels per second at 50 miles/hour.  There are 60 seconds per minute and 60 minutes per hour, so that's 3600 seconds in an hour

 

(60 x 60) = 3600.

 

Next, you can figure out how many feet the car travels per second.  In one hour, the car goes 5280 feet (per mile) times 50 (miles per hour) or 264000 feet per hour.

 

(5280 x 50) = 264000

 

Then divide by 3600 to determine feet per second (3600 seconds in an hour), which is 73 1/3 feet per second. 

 

264000/3600 = 73 1/3

 

The question is how many feet long was the tunnel if you hold your breath for 8 seconds, so I assume that it takes 8 seconds to drive through the tunnel.  The answer is 73 1/3 (feet per second) times 8 seconds, which is 586 2/3 feet, or 587 feet rounded.

 

(220/3) x 8 = 586 2/3

 

 

Answer 2

Are you saying that it took 8 seconds to exit the tunnel and you held your breath during that time because you were afraid while in the tunnel??

 

8 sec = 8/60 minute = 2/15 minute

 

                             = (2/15)(1/60) hr = 1/450 hr

 

Distance = (Rate)(Time) = (50 mi/hr)(1/450 hr) = 1/9 mile

 

                                                                   = (1/9)(5280) ft

 

                                                                   = 586 2/3 ft

 

 

Answer 3

Other tutors have worked this problem in steps, but you should learn the importance of units and how to convert them.  The basic principle is the Multiplicative Identity:  Multiply a number by 1 and it doesn't change.

 

For example, to change 7920 feet to miles, multiply by (1 mile / 5280 feet) and feet cancel out leaving 1.5 miles.

     7920*(1/5280) mi. = 1.5 mi.

 

This is a D-I-R-T (Distance-Is-Rate-times-Time) problem ("How many feet long was the tunnel?")

 

So, D = (50 mi/hr)(8 sec)

  but we want the answer in feet; also we want hr and sec to cancel out.

 

   D = (50 mi/ hr)(8 sec)( 5280 ft / 1 mi )( 1 min / 60 sec)(1 hr / 60 min)   [leaves only ft.]

   D = (50)(8)(5280) / (60*60)   ft.

   D = 586 2/3 ft,