#1 - Distance Time Riddle

Before the start of the car race, Tony Stewart and Jamie Mcmurray have the same amount of fuel in the car. With this fuel Tony Stewart can drive for 4 hours while Jamie can drive five hours.
After a time they realize that amount of fuel left in Tony car is 1/4th of the fuel in Jamie car.

For long they are racing ?

View Answer Discuss

15/4 hours

Explanation:
Let us say they drive for "t" hours and initial fuel is "f"

Amount of fuel used by Tony car is ft/4
Amount of fuel used by Jamie car is ft/5

As per given condition,
f - ft/5 = 4(f-ft/4)
Solving, t = 15/4 hours




#2 - John Watson Time Puzzle

The train leaves from New York City every 40 minutes from Boardman station. A man told John Watson that the train had left 15 minutes ago and the next train to New York City will leave at 9:40 p.m.

At what time, man convey this information to John Watson?

View Answer Discuss

Time of John Watson last missed the train = 8:40 PM - 40 min = 8:00 PM As this information has been given to John Watson 15 minutes after the train has already left, the man gave the information at 8:00 p.m. + 15 min = 8:15 PM

#3 - Find The Distance Puzzle

Two friends P and Q live near each other home. They both start driving towards each other at a constant speed. Both of them Meet 500 yards from P house. When they reach each other house, they start driving back and this time, they meet 300 yards away from Q house.

Can you find out the distance between P and Q ?

View Answer Discuss

Let us assume that the distance between P house and Q house be D.
Upon their first meet, P has traveled 500 yards.
Thus the distance traveled by Q = D - 500.
Calculating D as a multiple of 100 to simplify the equation
=> Speed of P / Speed of Q = 5 / (D - 5)..... (a)

Upon their next meet, P has traveled (D - 500) + 300
Distance traveled by Q = 500 + D - 300
=> Speed of P / Speed of Q = (D - 2) / (D + 2) ..... (b)

When we equate (a) and (b)
5 / (D - 5) = (D - 2) / (D + 2)
D = 12

Therefore, the distance between P and Q house is 1200 Yards.

#4 - Driving Car Time Puzzle

Two friends hit the accelerator of their respective cars at the same time. Both of them have the same amount of petrol in their respective cars at the time they start. One can drive for 4 hours and the other can drive for 5 hours.
After driving for a while, they analyse that the amount of petrol left in one of their cars is 4 times that of the petrol left in other car.

Can you calculate how long they have been driving their respective cars ?

View Answer Discuss

3.75

This question can be solved mathematically.
Let us assume that the initial amount of petrol is p.
The time for which they drove be t.
Now, the amount of petrol used by one car in t hours will be = pt / 4
The amount of petrol used by the second car in t hours will be = pt / 5
Now, the petrol left in the first car will be = (p - pt / 4)
The petrol left in the second car will be = (p - pt / 5)
According to the question
P - pt / 5 = 4(p - pt / 4)
T = 15 / 4 or 3.75 hours.
Therefore, both of the friends have driven the car for 3.75 hours.

#5 - Logic Container Time Puzzle

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double it was.


In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled half?

View Answer Discuss

The answer is 9 hours.


Since we know that the water becomes double in the quantity every passing hour and that it was filled completely in ten hours, we need to go back one-step. Take out one hour and divide the quantity by 2.

#6 - House Distance Puzzle

In a town, there are four houses located at different distances from each other. Following are the distances:
The third house is 60 km apart from the first house.
The fourth house is 40 km apart from the second house.
The third house is 10 km nearer to the fourth house than it is to the second house.

Can you find out the distance between the fourth and the first house ?

View Answer Discuss

75km

Distance between second and fourth house = 40 km

Distance between the second and third house + Distance between the third and fourth house = 40 km.

Distance between the second and third house + (Distance between the second and third house - 10) = 40 km.

Therefore,
2 * Distance between the second and third house = 50 km
=> Distance between the second and third house = 25 km

Hence, distance between the third and fourth house = 15 km

Distance between the first and fourth village = 60 + 15 = 75 km

#7 - Clock Time Puzzle

When a clock is observed, the hour hand is at a minute mark and the minutes hand is six minutes ahead of it.

When the clock is observed again after some time, the hour hand is precisely on a different minute mark and the minute hand is seven minutes ahead of it.

Can you calculate how much time has elapsed between the two observations?

View Answer Discuss

When the first observation was made, the time was 1:12 and when the second observation was made, the time was 3:24.

Therefore, 2 hours and 12 minutes have passed since the first observation.

#8 - Calculate Time Puzzle

Amy was sitting in front of a clock. When she observed it for the first time, the hour hand was at a minute mark and the minute hand was six minutes ahead it.

After some time, she observed the clock again to find that the hour hand was exactly on a different minute mark and the minute hand was seven minutes ahead of its time.

Can you calculate how much time has elapsed between two observations?

View Answer Discuss

When Amy first observed, the time was 1:12 and when she noticed again, the time was 3:24. Hence, 2 hours and 12 minutes have passed between two observations.

#9 - Drive Time Maths Puzzle

Alpha and Beta have same amount of petrol in their respective cars. Alpha can drive for 4 hours whereas Beta can drive for 5 hours with the amount of petrol left.

Both of them start driving at the same time. After a few hours, they find out that the amount of petrol remaining in one of the cars is four times the other car.

Can you calculate for how long did they drive the cars?

View Answer Discuss

3 3/4 hours

Assume that the initial amount of petrol in each of the petrol tanks be P.
Now, let us assume that they drove for H hours.

In that case, the amount of petrol used by one car in H hours will be = P*H /4
The amount of petrol used by the other car will be = P*H/5

Therefore, the petrol left in one car = P - P*H / 4
Petrol left in the other car = P - P*H / 5

Now, according to the question,
P - P*H / 5 = 4 (P - P*H / 4)
=> H = 15 / 4 = 3 3/4 hours.

#10 - Distance Math Problem

There is a straight highway. Four different villages lie on that highway. The distance between them is different. The third village is 60km away from the first village; the fourth is 40 km away from the second; the third is 10 km near to the fourth that it is to the second.

Can you calculate the distance between the fourth and the first village ?

View Answer Discuss

75

First Village = A
Second Village = B
Third Village = C
Fourth Village = D

Distance between B and D = 40km
=> Distance between B and C + Distance between C and D = 40km
=> Distance between B and C + (Distance between B and C - 10) = 40 km
=> 2 * Distance between B and C = 50km
=> Distance between B and C = 25km

Therefore distance between C and D = 15km

Thus, distance between A and D = 60 + 15 = 75km