A certain car travels a mile at 60 mph. It spends one second less to t

Take it step by step. We don't know the amount of time it takes to travel the first mile, and we'll need to know that in order to subtract one second from it. So, start there.

Distance = Rate * Time
1 mile = 60 mph * Time
Time = 1 mile / 60 mph = 1/60 hours

We need this time in seconds, though, not hours. Here's the safest way to convert, if you don't immediately recognize this value as being equal to 1 minute or 60 seconds.

\(\frac{1}{60}\) hours * \(\frac{60 minutes}{1 hour}\) * \(\frac{60 seconds}{1 minute}\)

\(\frac{1}{60}\) * \(\frac{60}{1}\) * \(\frac{60 seconds}{1}\)

60 seconds

So, the first mile took 60 seconds, and the second mile took 1 second less, or 59 seconds.

The question asks for the rate in miles per hour, so this has to get converted back to hours. Do the same thing, except backwards:

59 seconds * \(\frac{1 minute}{60 seconds}\) * \(\frac{1 hour}{60 minutes}\)

59 * \(\frac{1}{60}\) * \(\frac{1}{60}\) hours

59/3600 hours

Finally, use another distance/rate/time equation to find the rate:

1 mile = Rate * 59/3600 hours

Rate = 1/(59/3600) miles/hours = 3600/59 miles per hour

However, this would also be a great problem to guess on. The difference in time is only a single second. Because you're going faster, the speed should increase, not decrease. However, it should only increase by a small amount - a larger change would probably cause a bigger change in the time to travel one mile. Guess either (B) or (C).

First Mile: v = 60mph; distance = 1 mile => time = 60 seconds

Second Mile: V = ?; distance = 1 mile => time = 59 seconds
v = distance/time = 1mile/59 seconds (* 59 seconds = 59/60*60 hrs)
v = 1 mile(60*60)/59 mph = 3600/59 mph => Option C correct

time per mile ; 1/60 hrs or say ; 3600/60 ; 60 seconds
next mile is covered in 1 second less ; 59 seconds
so the avg speed for next mile ; 59/3600 hrs or say 1/59 *3600 = 3600/59 mph
IMO C

At a rate of 60 mph, it takes 1/60 hour = 1/60 x 3600 = 60 seconds to travel 1 mile. So the next mile takes 59 seconds, and the rate is 1/59 mile per second, or 1/59 x 3600 = 3600/59 mph.

Answer: C