Shortcut and Tricks: Computational Speed
Increase your mental calculation speed. It is essential that you develop an ability to calculate 10%, 1%, 2%, 5% of random numbers. You should be able to calculate average of six three-digit numbers in less than thirty seconds.
e.g. to find the average of 514, 368, 975, 140, 674, and 807.
Be Meticulous
Look for the following:
- Units:
- Respect Footnotes:
- Understand Percentage:
- Rapid Eye Movement:
Develop a Sense of Approximation
Grasp the following illustration:
RVG Hospital | PKR Clinic | JP Hospital | |
Tuberculosis | 123 | 201 | 68 |
AIDS | 41 | 61 | 34 |
Leukaemia | 23 | 79 | 47 |
Laryngitis | 18 | 8 | 12 |
Neurosis | 16 | 6 | 74 |
A
The average number of tuberculosis patients in the three institutions is nearly
- 147
- 169
- 131
- 119
(Now the untrained candidate would add 123, 201 and 68 and divide by 3 to get the answer. What the smart candidate does is to add 120, 200 and 70, gets a total of 390 and divides by 3 to get 130 and so marks the choice (c))
B
The RVG Hospital has what per cent less patients in AIDS than those in PKR Clinic?
- 34.45
- 32.78
- 35.68
- 30.78
Solution
(Again the smart candidate finds 20 is what per cent of 60, it being 33.33%, understands the actual answer should be slightly less and thus marks choice (b), whereas the dumb candidate actually does the operation 20/61*100, wasting valuable time.)