edited by
1,968 views
0 0 votes

$A$ can do a piece of work in $14$ days which $B$ can do in $21$ days. They begin together but $3$ days before the completion of the work, $A$ leaves off. The total number of days to complete the work is :

  1. $\frac{33}{5}$
  2. $8\frac{1}{2}$
  3. $\frac{51}{5}$
  4. $13\frac{1}{2}$

1 Answer

Best answer
1 1 vote

Answer is C

x days (A and B work together) + 3 days (B alone worked) = 1

$x*(\frac{1}{14}+\frac{1}{21})+ 3*\frac{1}{21}=1$

On solving, we will get $5x = 36 \implies x =\frac{36}{5}$

Therefore, total number of days to complete the work = $\frac{36}{5}$ + 3 = $\frac{51}{5}$

selected by
Position:
Show:
Answer:

Related questions

0 0 votes
1 answers 1 answer
2.1k
2.1k views
Lakshman Bhaiya asked Apr 3, 2020
2,104 views
If $9$ men working $7\frac{1}{2}$ hours a day can finish a work in $20$ days, then how many days will be taken by $12$ men working $6$ hours a day to finish the work, it ...
0 0 votes
1 1 answer
2.1k
2.1k views
Lakshman Bhaiya asked Apr 3, 2020
2,052 views
If $A$ be the area of a right angled triangle and $b$ be one of the sides containing the right angle, then the length of altitude on the hypotenuse is :$\frac{2Ab}{\sqrt{...
0 0 votes
1 answers 1 answer
2.2k
2.2k views
Lakshman Bhaiya asked Apr 3, 2020
2,180 views
The $L.C.M$ of $\left (x^{3}-x^{2}-2x \right)$ and $\left (x^{3}+x^{2} \right)$ is : $\left (x^{3}-x^{2}-2x \right)$$\left (x^{2}+x \right)$$\left (x^{4}-x^{3}-2x^{2} \ri...
0 0 votes
1 1 answer
2.5k
2.5k views
Lakshman Bhaiya asked Apr 3, 2020
2,491 views
Ashok's age is $\left (\frac{1}{6} \right)^{th}$ of his father's age. The father's age will be twice of Kamal's age after $10$ years. If Kamal's eighth birthday was celeb...
1 1 vote
1 1 answer
1.9k
1.9k views
Lakshman Bhaiya asked Apr 3, 2020
1,853 views
If $t^{2}-4t+1=0$, then the value of $\left[t^{3}+1/t^{3} \right]$ is :$44$$48$$52$$64$