Time and Work is an important chapter for bank exams. This post is a part of "Shortcut Techniques" series where I decided to share shortcut techniques related quantitative techniques that can be used in IBPS exam or any other competitive exam.

Time and work is an important topic in IBPS exams, including clerks, PO and specialist officers.

## Shortcut

Best trick that I use in exams myself is by finding the efficiency of workers in percent. If A can do a job in 2 days then he can do 50% in a day.

Number of daysrequired to complete the work | Work that can be done per day | Efficiency in Percent |
---|---|---|

n | 1/n | 100/n |

1 | 1/1 | 100% |

2 | 1/2 | 50% |

3 | 1/3 | 33.33% |

4 | 1/4 | 25% |

5 | 1/5 | 20% |

6 | 1/6 | 16.66% |

7 | 1/7 | 14.28% |

8 | 1/8 | 12.5% |

9 | 1/9 | 11.11% |

10 | 1/10 | 10% |

11 | 1/11 | 9.09% |

### Now let's solve questions with this trick

**Solution -**A's efficiency = 20%, B's efficiency = 10%. If they work together they can do 30% of the job in a day. To complete the job they need 3.33 days.

**Solution**- Let efficiency percentage as x

⇒ A's efficiency = 2x and B's efficiency = x

⇒ A is twice efficient and can complete the job 30 days before B. So,

⇒ A can complete the job in 30 days and B can complete the job in 60 days

⇒ A's efficiency = 1/30 = 3.33%

⇒ B's efficiency = 1/60 = 1.66%

⇒ Both can do 5% ( 3.33% + 1.66% ) of the job in 1 day.

So the can complete the whole job in 20 days (100/5)

**Solution**-

**Method 1**

⇒ Efficiency of filling pipe = 20 minutes = 1/3 hour = 300%

⇒ Efficiency of leakage = 60 minutes = 100%

We need to deduct efficiency of leakage so final efficiency is 200%. We are taking 100% = 1 Hour as a base so the answer is 30 minutes.

⇒ Efficiency of filling pipe = 100/20 = 5%

⇒ Efficiency of leakage pipe = 100/60 = 1.66%

⇒ Net filling efficiency = 3.33%

So tank can be filled in = 100/3.33% = 30 minutes

**Update**- 09-09-2013 ( As Shobhna and Aswin are facing problem in solving this question, I am solving this question with the second method which is also very easy, hope this will make the solution lot easier.)**Method 2**⇒ Efficiency of filling pipe = 100/20 = 5%

⇒ Efficiency of leakage pipe = 100/60 = 1.66%

⇒ Net filling efficiency = 3.33%

So tank can be filled in = 100/3.33% = 30 minutes

You can change the base to minutes or even seconds.

You can solve every time and work question with this trick. In above examples, I wrote even simple calculations. While in exams you can do these calculations mentally and save lots of time.

You can find more tricks like this in quantitative aptitude section.

Comment below in case of any query, I promise to reply within 24 hours.

Comment below in case of any query, I promise to reply within 24 hours.

**Update**- Question requested by Chitra Salin**Solution -**Let number of men =x, number of women = y

⇒ Efficiency of 4 men and 6 women = 100/10 = 10%

⇒ so, 4x+6y = 10

Above equation means 4 men and 6 women can do 10% of the job in one day.

⇒ Efficiency of 3 men and 7 women = 100/8 = 12.5%

so, 3x+7y = 12.5

By solving both equations we get, x = -0.5 and y = 2

⇒ Efficiency of 1 woman(y) = 2% per day

⇒ Efficiency of 10 women per day = 20%

So 10 women can complete the job in 100/20 = 5 days

**Update**Question requested by Praisy

**Solution -**

⇒ Efficiency of A and B = 1/20 per day = 5% per day ________________1

⇒ Efficiency of B and C = 1/30 per day = 3.33% per day______________2

⇒ Efficiency of C and A = 1/30 per day = 3.33% per day______________3

Taking equation 2 and 3 together

⇒ B + C = 3.33% and C + A = 3.33%

⇒ C and 3.33% will be removed. Hence A = B

⇒ Efficiency of A = B = 5%/2 = 2.5% = 1/40

⇒ Efficiency of C = 3.33% - 2.5% = 0.833% = 1/120

⇒ A can do the job in 40 days and C can do the job in 120 days he they work alone.

⇒ Ratio of number of days in which A and C can complete the job 1:3.

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