Maths Puzzles

 Yet another simple puzzle Peter has three times as many sisters as brothers. His sister Louise has twice as many sisters as brothers. How many children are there in the family?

Here is non-tricky question - quite simple one ​ An accurate clock shows 8 o'clock in the morning. Through how may degrees will the hour hand rotate when the clock shows 2 o'clock in the afternoon? i) 144º iii) 150º iii) 168º iv) 180º

The puzzle was  There is a closet and a light bulb inside this closet. You can not see whether the bulb is on or off from outside. There are three switches outside the closet one of which controls the light bulb. You can not see these switches from the closet. How do you find out which switch controls the bulb with a single try? Now let us look at the solution. Switch on the first switch wait for 2-3 minutes and then switch it off. Switch on the second switch. Now go inside the closet. If the bulb is on, then second switch is the switch for the bulb. If bulb is off, touch it. If it is warm then first switch is the switch. If not third switch is the switch for the bulb

 Here is an easy logical puzzle. And many of you already know the solution. There is a closet and a light bulb inside this closet. You can not see whether the bulb is on or off from outside. There are three switches outside the closet one of which controls the light bulb. You can not see these switches from the closet. How do you find out which switch controls the bulb with a single try?

Let us assume that on that day, Amanda took t minutes to drive half way to her son's school and back home. And as she reached home 40 minutes early, it would have taken t+40 minutes usually. Let us say Amanda meets her son returning from school at point P. So the travel from P to school and back to P would have caused extra 40 minutes normally. As she is traveling in a constant speed, the one way journey from point P to Mat's school would take half the time - 20 minutes.  Amanda would have reached school at 5 pm. Which means she reached point P at 5 pm - 20 minutes = 4:40 pm. So Amanda meets her son at 4:40 pm. Now Mat has traveled one hour before meeting his mother - so he has started from school at 3:40 pm.  As chess club completes at 5 pm, he has missed 1 hour and 20 minutes of chess practice.

This puzzle is from popular-mechanics.    Amanda lives quite close to her son Mat's school. Every evening she leaves exactly at the same time and travels in her car in a constant speed and picks up Mat after his chess club ends at 5 pm and brings him back at the same constant speed.  One day, Mat is having a headache and leaves chess club early and starts going home in his portable scooter in their usual route. After he has been scooting for an hour, Amanda meets him on the road, picks him up and they come home together in her car. They reach home 40 minutes earlier than usual. How much of the chess practice did Mat miss?    Find the solution here .

 I will give you the solution of bonus question first.  The answer is infinite speed Question was :   Tom wants to travel from San Francisco to  Los Angeles and back - a round trip -  with an average speed of 50 mph. If you are feeling very patriotic change the name of the person to Suresh and cities to Delhi and Agra.  Due to traffic, he could travel only at 25 mph on the way to Los Angeles. What must be his speed on return journey in order to get an average speed of 50 mph. Here is  why Let us distance between the two cities is x.  So Tom wants to travel the round trip in - 2x/50 hours - the distance being 2x = x/25 hours . The total time = x/25 Now for onward journey he has taken x/25 hours - x miles with the speed of 25 mph. So which means he has to cover the rest of the distance - x miles in a time of total time - x/25 = x/25 - x/25 = 0 hours The speed needed will be x/0 = infinite.  And the other question was  How do we get 10 using 1,1, 5 and 8 using all of these and any

 Today I have a simple puzzle and a bonus puzzle.     Can you get 10 using the numbers 1 1 5 and 8. You have to use all numbers. You can use any operator. Bonus puzzle :   Tom wants to travel from San Francisco to  Los Angeles and back - a round trip -  with an average speed of 50 mph. If you are feeling very patriotic change the name of the person to Suresh and cities to Delhi and Agra.  Due to traffic, he could travel only at 25 mph on the way to Los Angeles. What must be his speed on return journey in order to get an average speed of 50 mph. Believe me, the solution is really interesting.  By the way, if you like numbers, you may love my app Shataka . Give it a try.    You will find the solution to both the puzzles here .