# Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 28)

28.

X can do a piece of work in 40 days. He works at it for 8 days and then Y finished it in 16 days. How long will they together take to complete the work?

Answer: Option

Explanation:

Work done by X in 8 days = | 1 | x 8 | = | 1 | . | ||

40 | 5 |

Remaining work = | 1 - | 1 | = | 4 | . | ||

5 | 5 |

Now, | 4 | work is done by Y in 16 days. |

5 |

Whole work will be done by Y in | 16 x | 5 | = 20 days. | ||

4 |

X's 1 day's work = | 1 | , Y's 1 day's work = | 1 | . |

40 | 20 |

(X + Y)'s 1 day's work = | 1 | + | 1 | = | 3 | . | ||

40 | 20 | 40 |

Hence, X and Y will together complete the work in | 40 | = 13 | 1 | days. | ||

3 | 3 |

Discussion:

31 comments Page 4 of 4.
SHEIK said:
1 decade ago

x can do work=1/40--->1

Let 8x+16y=1---->2(which is x &y can do work)

sub x value in above equ. we get

8(1/40)+16y=1

y=1/20.

finally, x=y will together=(1/40)+(1/20)=3/40

Hence, ans is (40/3)=13 1/3 days...

Let 8x+16y=1---->2(which is x &y can do work)

sub x value in above equ. we get

8(1/40)+16y=1

y=1/20.

finally, x=y will together=(1/40)+(1/20)=3/40

Hence, ans is (40/3)=13 1/3 days...

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