Sheldon had to cover a distance of 60 km. However, he started 6 minutes later than his scheduled time and raced at a speed 1 km/h higher than his originally planned speed and reached the finish at the time he would reach it if he began to race strictly at the appointed time and raced with the assumed speed. Find the speed at which he travelled during the journey described.

a)
25 km/h

b)
10 km/h

c)
6 km/h

d)
15 km/h

Correct answer is option 'A'. Can you explain this answer?

Question

Sheldon had to cover a distance of 60 km. However, he started 6 minutes later than his scheduled time and raced at a speed 1 km/h higher than his originally planned speed and reached the finish at the time he would reach it if he began to race strictly at the appointed time and raced with the assumed speed. Find the speed at which he travelled during the journey described.

a)
25 km/h
b)
10 km/h
c)
6 km/h
d)
15 km/h

Correct answer is option 'A'. Can you explain this answer?

Answer

Amount of work P can do in 1 day = 1/20

Amount of work Q can do in 1 day = 1/30

Amount of work R can do in 1 day = 1/60

P is working alone and every third day Q and R is helping him

Work completed in every three days = 2 * (1/20) + (1/20 + 1/30 + 1/60) = 1/5

So work completed in 15 days = 5 * 1/5 = 1

Ie, the work will be done in 15 days

Answer

Let the total work be LCM of (20,30,60) = 60 units

P's 1 day work = 3 units. but P works for all 3 days so units done by P = 3 x 3 = 9

Q's 1 day work = 2 units.

R's 1 day work = 1 unit.

units done by P+R+Q at the end of the 3rd day = 9+2+1 = 12 units

required days = 3/12 x 60 = 15 days

Answer

Given:
Distance to be covered, d = 60 km
Delay in starting, t = 6 minutes = 1/10 hour
Let the originally planned speed be x km/h.
Sheldon's speed in the actual race = (x+1) km/h

To find:
The speed at which Sheldon travelled during the journey described.

Solution:
Let's assume that Sheldon took 't' hours to complete the race at the speed of 'x' km/h.
So, the time taken to cover the distance of 60 km at the speed of 'x' km/h would be:
t = d/x

According to the given condition, Sheldon started 6 minutes (1/10 hour) late and completed the race at the same time as he would have completed if he had started on time and raced at the planned speed. This means that he took less time than 't' hours to complete the race.

Let's say he took 'h' hours to complete the race at the speed of (x+1) km/h.
So, the time taken to cover the distance of 60 km at the speed of (x+1) km/h would be:
h = d/(x+1)

According to the question, h = t - 1/10
d/(x+1) = d/x - 1/10
Solving the above equation, we get:
x = 24 km/h

So, the speed at which Sheldon travelled during the journey described = x+1 = 24+1 = 25 km/h

Therefore, option 'A' is the correct answer.

Answer

15 days

Answer

All options will satisfy with 0.1 why you are saying that option a is the correct answer.....if we calculate speed = distance/time. Then we get 1=60/6...Then the answer would be 10....

Answer

Solve this question through options.
⇒ For instance, if he travelled at 25 km/h, his original speed would have been 24 km/h.
⇒ The time difference can be seen to be 6 minutes in this case = 60 / 24 – 60 / 25 = 0.1 hrs = 6 mins

Thus, 25 km/h is the correct answer.

So Option A is correct

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