Quicker Maths
4Feb/122

The Superstitious Boss

Apply your Mind

Ramlal is a night watchman in a large company. On one fine morning when Ramlal was about to leave for home, his boss informs him, “I'll go for a business trip to Colombo. Tomorrow I will depart from Chennai airport”.

Ramlal, however advises him to take a ship.

“Why should I?” inquired the boss.

“Yesterday night I dreamt that the plane to Colombo crashes, just before it will land”, is the response from Ramlal.

The president smiles first, but since he is pretty superstitious he decides to take the ship. When he arrives in Colombo, he is told that the plane which he should have taken had crashed. When the president returns from the trip, he gives a big reward to Ramlal and immediately fires him. Why?

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29Jan/120

Current Affairs Books 2012

Current affairs | general awareness | general knowledge section is as important as any other section in almost all government job competitive examinations. To improve our overall awareness there are lots of options like internet, newspapers, magazines, etc.  However, there are very few options for exam specific preparation. The most striking part of this section is that there cannot be any prescribed format to prepare oneself for it. Fortunately, there are some wonderful books which can help you to sail through these competitive examinations. I am listing the most trusted books on current affairs and general awareness below.

Manorama Yearbook 2012 (Free CD)This best seller has a long history of success. It is India's best General knowledge update covering almost everything that a student needs in competitive examinations Purchase Online

20Jan/123

No More Carrying Over

"Carry" in Addition - Can it be Avoided?

Carrying over is a concept taught to us at a very early stage of our life. However, it has never been an easy thing to do. In adding two or more numbers, most of us face problem while “carrying over”. Larger the digits, involved in the numbers to be added, more likely it is to involve carrying.   More the carrying over involved, more likely are we to make mistakes.

Friends, remember the most basic and effective rule of making arithmetic fast and quick is to break difficult calculations into simpler, easily manageable small calculations.

Any digit when added to 9 (except 0) makes carrying over mandatory.  On the contrary, anything added to 0 can’t produce a two digit number.  Even if 9 is added to 0, no carrying is needed.

17Jan/120

Brain needs Exercise

This is a guest post by Amanda Tradwick 

Brain Games for Your Aging Parents

Just like any other part of the body, the brain has to be exercised to stay healthy. Just like strength training can help muscles to stay strong and running can help the heart stay healthy, regular cognitive exercise can help mental function to stay sharp and to stave off memory loss and dementia. Though the effects of age and time cannot be avoided over time, performing mental exercise can help delay those effects and keep the mind healthier for a longer period of time. Here's how brain games can help your aging parents:

Benefits

There are many benefits of brain games and other mental exercises, like learning new skills or hobbies. Here are a few of the benefits:

14Jan/120

Mathematics of Insurance

This is a guest post by Izzy Woods

Life Is A Gamble: Mathematics Of Expected Value And Insurance Explained

It’s always interesting when someone makes the claim that they don’t gamble. Even this early in the year most people will have made several decisions where the outcome was uncertain and those outcomes were mostly financial - just like a bet. Whether it was deciding to start the year with a new job or take out some kit car insurance on the newly built love of their lives they can’t be sure whether their financial position will be stronger or weaker as a result of their decision.

We’ll first explore the simple mathematics behind these gambles using a gambling example and explain why some decisions you should take each and every time they are offered to you. Interestingly products like insurance rely on our fear of ruin and are not always a fair gamble; we’ll explain why that is and how that leads to profit for insurance companies.

24Dec/1118

Imagine you are in a room with 3 switches

IQ Test

Imagine you are in a big house and you need to match out the 3 switches located in the first floor with the three light bulbs located in the ground floor. In the ground floor there are 3 bulbs (all are off at the moment), each switch belongs to some bulb.

Question

How can you find out, which switch belongs to which bulb?

Other conditions

It is impossible to see from one room to another.

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22Dec/110

Real Estate Math Problem

Math problems dealing with real estate, debt and income can be a little tricky, but fun and extremely useful in the real world! Check out this real estate math problem to see if you can find the solution!

This puzzle is a DTI--Debt-to-Income--problem that banks usually utilize to calculate whether or not a potential borrower will be able to pay back the loan.

Background Info: Mr. and Mrs. Abrams have a combined yearly income of $90,000. They would like to purchase a commercial property on which to start a business for $215,000. They have spoken with a potential lender, who indicated they can provide a $200,000, 30 year loan at 7% interest if the Abrams can qualify. In addition to the property payment, the Abrams estimate their taxes and insurance to be $145 per month. Mr. Abrams has a student loan payment of $67 a month and Mrs. Abrams has a car payment of $347 a month. Assume an amortization factor of 6.65.

17Dec/112

The Pierrot Puzzle

Question on Special Products

The Pierrot in the illustration is standing in a posture that represents the sign of multiplication. He is indicating the peculiar fact that 15 multiplied by 93 produces exactly the same figures (1,395), differently arranged.

The puzzle is to take any four digits you like (all different) and similarly arrange them so that the number formed on one side of the Pierrot when multiplied by the number on the other side shall produce the same figures. There are very few ways of doing it, and you shall give all the cases possible. Can you find them all?

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4Dec/1112

Benediktov Problem

Tricky Problem

The Great Russian poet Benediktov was very fond of mathematics and he collected and compiled a whole volume of trick brain teasers. Though this work was never published, the manuscript was found in 1924. An interesting problem contained in the manuscript, captioned ‘An ingenious Way of Solving a Tricky Problem’ goes as follows:

One woman made a living by selling eggs, had 90 eggs which she wanted her three daughters to sell. So she gave her eldest daughter 10 eggs, 30 to her second daughter and 50 to the youngest.

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20Nov/1111

Rule of 72 – Estimation of Compound Interest and Time

Effect of Compounding

The Rule of 72 is a good quick math shortcut to find out the following –

  • Time required for an amount to double itself, at a given rate of interest
  • Rate at which an amount should grow to double itself in given time

This formula can be applied for “Doubling Problems” related to money, population, etc. which grows at an annual compounded rate.

Formulae

  1. To calculate the time; T = 72/R
  2. To calculate the rate of interest; R= 72/T