Question

. Jones covered a distance of 50 miles on his first trip. On a later trip he traveled 300 miles while going three times as fast. His new time compared with the old time was:

(a) three times as much, (b) twice as much, (c) the same, (d) half as much, (e) a third as much
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Answer 1

Answer:

Let speed of the 1st trip x miles / hr. and speed of the 2nd trip 3x / hr.

We know that

Speed = Distance/Time.

Or, Time = Distance/Speed.

So, times taken to covered a distance of 50 miles on his first trip = 50/x hr.

And times taken to covered a distance of 300 miles on his later trip = 300/3x hr.

= 100/x hr.

So we can clearly see that his new time compared with the old time was: twice as much.

Answer: (b)

Answer 2

The correct answer is option B.

Given: Distance covered in first trip = 50 miles.

Distance covered in second trip = 300 miles.

To Find: Time covered in second trip.

Solution:

Speed in first trip = x

Speed in second trip = 3x

$Time= \frac{Distance}{Speed}$

= $\frac{50}{x}$

Time taken in first trip = $\frac{50}{x}$

$Time= \frac{Distance}{Speed}$

= $\frac{300}{3x}$

= $\frac{100}{x}$

Time taken in second trip = $\frac{100}{x}$ = $2(\frac{50}{x} )$

= 2(Time taken in first trip)

Hence, time taken in second trip is twice the time taken in first trip.

#SPJ3