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Quantitative Aptitude: Speed Maths: Usefulness of powers of 3

jagranjosh.com has come up with some importants tips of Speed Maths for the aspirants.

Feb 10, 2016 17:16 IST
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Jagranjosh.com has brought up concept ‘power of 3’ to help the aspirants in attempting all the questions speedily. Here, we are providing basic concepts to make the calculation faster than doing from long and traditional ones. Practice and thorough learning of some values can help the candidates in cracking Quantitative Aptitude/Numerical Ability Section in Bank Exam, SSC Exam, Railway and Other Exam.

3

1

32

9

33

27

34

81

35

243

36

729

First have a look at the powers of 3 upto 6 given above

The sum of the numbers 3, 31, 32 and 33 (i.e. 1, 3, 9 and 27) is 40. Using a combination of these numbers we can obtain any number from 1 to 40.

For Example:

2=3-1;

4=1+3;

5=1+1+3; and so on..  40=1+3+9+27

  • Each occurring at the most once we can obtain all the numbers from 1 to 40 by using the operations of only addition and/or subtraction.
  • In other words if you have one each of the weights of 1 kg, 3 kg, 9 kg and 27 kg, by using a combination of these weights in EITHER one of the two pans of a weighing scale, we can weigh all weights from 1 kg to 40 kg. You are using the weights in 2 pans.
  • The above usefulness of the powers of 3 can be widely used in the questions of Quantitative Aptitude/Numerical Ability.

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