Quicker Maths
5Nov/095

The Cycle Race Brain Teaser

Krishna and Bala decided to have a bicycle race. But the problem was that they had only one bicycle between them! Krishna had a solution. As the road to the airport had a stone demarcating every kilometer, he would ride from the first stone to the fifth, and Bala could ride the remaining distance from the fifth to the tenth stone. Then they could take their respective times with a stopwatch to see who was faster. The ‘race’, however, was a failure. Can you say why?

Filed under: Puzzles 5 Comments
3Nov/0911

Vedic Multiplication of two numbers close to Hundred

Vedic Method of Multiplication: Base System of multiplication

Application: Multiplication of two numbers close to Hundred

Case 1: Both numbers greater than 100.

Rule: You will get the answer in two parts

First part, to get left hand side of the answer: Add the difference between 100 and either of the numbers to the other number

Second part, to get right hand side of the answer: multiply the difference from 100 of both the numbers

Example

103 x 104 = 10712

The answer is in two parts: 107 and 12,

107 is just 103 + 4 (or 104 + 3), and 12 is just 3 x 4.

Similarly 107 x 106 = 11342

107 + 6 = 113 and 7 x 6 = 42

123 x 103 = 12669

(123 + 3) | (23 x 3) = 126 | 69 =12669 .

 

If the multiplication of the offsets is more than 100 then this method won’t work. For example 123 x 105. Here offsets are 23 and 5.

Multiplication of 23 and 5 is 115 which are more than 100. So this method won’t work.

But it can still work with a little modification. Consider the following examples:

 

Example 1

122 x 123 = 15006

Step 1: 22 x 23 = 506 (as done earlier)

Step 2: 122 + 23 (as done earlier)

Step 3: Add the 5 (digit at 100s place) of 506 to step 2

Answer: (122 + 23 + 5) | (22 x 23) = 150 | 06 = 10506

 

Example 2

123 x 105 (Different representation but same method)

123 + 5 = 128

23 x 5 = 115

128 | 115

= 12915

 

In the next post I'll tell you about vedic multiplication, i.e.,  how to multiply two numbers lesser than the base (in this case 100).

Here's the promised post for you - http://www.quickermaths.com/base-method-of-multiplication/

If you liked this method of vedic multiplication included in ancient Vedic Maths, Please leave a comment to let us know.

3Nov/0910

Time and Speed Puzzle

Raja’s office is 9 km from his home. One day, he decided to jog to work in order to increase his fitness. He estimates the journey time to be a little over 1 hour 45 minutes.

At first he feels fine, but before long his energy beings to fade and he realizes he will not be able to run the whole distance. A passing taxi is the answer to his prayer. Raja hails the cab and completes his journey, arriving at work one hour 10 minutes earlier than he had anticipated.

Assuming Raja could at 1/6 the speed of the cab, how far did he run before he hailed the taxi?

Filed under: Puzzles 10 Comments
1Nov/095

Locker Puzzle : Maths Puzzle

A school had a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

Try and solve this logical maths puzzle yourself.

Filed under: Puzzles 5 Comments