Time and Work
- In a school, MID-Day meal food is sufficient for 250 students for 33 days. if each students is given 125 g meals. 80 more students joined the school. If same amount of meal is given to each student, then the food will last for
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M1 = 250, D 1 = 33 days
per day meal W1 = W2 = 125 g
M2 = (250 + 80) =330 and D2=?
According to the formula
M1D1W2 = M2D2W1Correct Option: D
M1 = 250, D 1 = 33 days
per day meal W1 = W2 = 125 g
M2 = (250 + 80) =330 and D2=?
According to the formula
M1D1W2 = M2D2W1
250 x 33 x 125 = 330 x D2x 125
⇒ D2 = (250 x 33)/330
∴ D2 = 25 days
- kavita, babita and samita started a work. 5 days later Samita left the work and Babita left the work after working 8 days. In how many more days Kavita would have completed the rest work if they take 20, 60 and 30 days individually to finish a work?
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Efficiency of Kavita = 5%
Efficiency of Babita = 1.66%
Efficiency of Samita = 3.33%
Work done in 5 days by K + B + S = 5 x 10 = 50%
Work done in 3 days by K + B = 3 x 6.66 = 20%Correct Option: C
Efficiency of Kavita = 5%
Efficiency of Babita = 1.66%
Efficiency of Samita = 3.33%
Work done in 5 days by K + B + S = 5 x 10 = 50%
Work done in 3 days by K + B = 3 x 6.66 = 20%
Remaning work (30%) done by Kavita alone = 30/5 = 6 days
- Kareena can do a piece of work in 9 days and Krishna can do the same work in 18 days. They started the work. After 3 days Shahid joined them, who can complete alone the same whole work in 3 days. What is the total No. of days in which they had completed the work?
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Efficiency of Kareena and Krishna = 11.11 + 5.55 = 16.66%
Work done in 3 days = 3 x 16.66 = 50%
Rest work done by Kareena, Krishna and Shahid = 50/50 = 1 day
(Since efficiency of Shahid = 33%)Correct Option: C
Efficiency of Kareena and Krishna = 11.11 + 5.55 = 16.66%
Work done in 3 days = 3 x 16.66 = 50%
Rest work done by Kareena, Krishna and Shahid = 50/50 = 1 day
(Since efficiency of Shahid = 33%)
Thus in ( 3 + 1) days they have completed the work = 4 days.
- Krishna can do a work in 10 days while Mohan can do the same work in 20 days. They started work together. After 3 days Krishna left the work and Mohan completed it. For how many days Mohan worked alone more than the No. of days required when both worked together?
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Krishna's efficiency = 10%
Mohan's efficiency = 5%
Work done by Krishana and mohan together in 3 days = 15 x 3 = 45%
Now, number of days in which B completed rest (55%) work alone = 55/5 = 11
Total No. of days in which B worked = 3 + 11 = 14Correct Option: A
Krishna's efficiency = 10%
Mohan's efficiency = 5%
Work done by Krishana and mohan together in 3 days = 15 x 3 = 45%
Now, number of days in which B completed rest (55%) work alone = 55/5 = 11
Total No. of days in which B worked = 3 + 11 = 14
Now No. of days required by B, when A and B both worked together = 100/15 = 62/3
∴ Required difference in No. of days = (11) - (62/3)
= 13/3 = 4 1/3 days
- Efficiency of Asha is 25% more then Usha and Usha takes 25 days to complete a piece of work. Asha started a work alone and then usha joined her 5 days before actual completion of the work. For how many days Asha worked alone?
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Efficiency (Asha : Usha) = 5 : 4
Number of days(Asha : Usha) = 4x : 5x = 4x : 25
∴ Number of days required by Asha to finish the work alone = 4x
= 4 x 5 = 20.
Now, since Asha and Usha did work together for last 5 days = 5 x 9 = 45%
(since efficiency of Asha = 5% and Usha's efficiency = 4%)
It means Asha completed 55% work alone.Correct Option: B
Efficiency (Asha : Usha) = 5 : 4
Number of days(Asha : Usha) = 4x : 5x = 4x : 25
∴ Number of days required by Asha to finish the work alone = 4x
= 4 x 5 = 20.
Now, since Asha and Usha did work together for last 5 days = 5 x 9 = 45%
(since efficiency of Asha = 5% and Usha's efficiency = 4%)
It means Asha completed 55% work alone.
∴ No. of days taken by Asha to complete 55% work = 55/5 = 11days
