Q1. A and B working together can do a piece of work in 4 1/2 hours. B and C working together can do it in 3 hours. C and A working together can do it in 2 1/4 hours. All of them begin work at the same time. Find how much time they will take to finish the piece of work?
A. 3 hours
B. 2 hours
C. 2.5 hours
D. 1 hours
Answer: B
Explanation:
Total efficiency = [latex]\frac {9}{2} [/latex]
Time = 2 hours
Q2. Ram decided to plow farmland in 50 days. He employed 50 men in the beginning and 50 more after 35 days and completed the construction in stipulated time. If he had not employed the additional men, how many days behind schedule would it have been finished?
A. 5 days
B. 6 days
C. 8 days
D. 10 days
Answer: A
Explanation:
Given that, 50 men employed for 35 days and 50 more men employed for 15 days so that the work could be finished in 50 days.
Thus, the total work = [latex] 50 \times 35 + (50 + 50) 15 [/latex] = 3250
Suppose, it takes [latex] x [/latex] days to finish the whole work if additional men were not employed.
So, we have an equation here.
[latex] 50 \times x [/latex] = 3250
[latex] x [/latex] = 65 days
Therefore, it takes 15 days more than the stipulated time.
Q3. The work done by a woman in 8 hours is equal to the work done by a man in 6 hours and by a boy in 12 hours. If working 6 hours per day 9 men can complete a work in 6 days then in how many days can 12 men, 12 women and 12 boys together finish the same work working 8 hours per day?
A. 1 [latex] \frac {1}{2} [/latex] days
B. 3 [latex] \frac {2}{3} [/latex] days
C. 3 days
D. 2 [latex] \frac {1}{2} [/latex] days
Answer: A
Explanation:
8 Women = 6 Men = 12 Boys
12M + 12W + 12B = 12M + 9M + 6M = 27M
Now, applying the above formula, we have
[latex]9 \times 6 \times 6 = 27 \times 8 \times [D]_[2] [/latex]
[latex] [D]_[2] = \frac {9 \times 6 \times 6}{27 \times 8} = 1 \frac {1}{2} [/latex] days
Q4. A and B can do a piece of work in 10 days, B and C in 15 days and C and A in 20 days. They all work at it for 6 days, and then A leaves, and B and C go on together for 4 days more. If B then leaves, how long will C take to complete the work?
A. 20 days
B. 25 days
C. 10 days
D. 15 days
Answer: C
Explanation:
Amount of work done by A, B and C together in aday is [latex] \frac {6 + 4 + 3}{2 \times 60} = \frac {13}{120} [/latex]
Work done by all in 6 days = [/latex] \frac {13}{120} [/latex]
Work done by B and C in 4 days = [latex]\frac {4}{15}[/latex]
Remaining work = 1 - [latex](\frac {13}{20} + \frac {4}{15})[/latex]
= [latex]\frac {1}{2}[/latex], which is to be done C
Now, from the question,
C alone can do the whole work in [latex]\frac {\frac {120}{18}\times {10}}{10 - \frac {120}{18}}[/latex] = 120 days
therefore, [latex]\frac {1}{12}[/latex] of the work is done by C [latex]\frac {120}{12}[/latex] = 10 days
Q5. Amit and Sujit together can complete an assignment of Data entry in 5 days. Sujit’s speed is 80 % of Amit’s speed and the total key depressions in the assignment are 5,76,000. What is Amit’s speed in key depressions per hour if they work for 4 hours a day?
A. 14800
B. 16400
C. 16000
D. 17200
Answer: C
Explanation:
Amit + Sujith = 5 days
Let Amit = [latex] x [/latex] days
Sujith = [latex]\frac {180 x}{100} = \frac {4 x}{5}[/latex] days
now,
[latex]\frac {1}{x} + \frac {5}{4x} = \frac {1}{5}[/latex]
[latex]\frac {4 + 5}{4 x} = \frac {1}{5} [/latex]
[latex] \frac {45}{4} [/latex]
therefore, Amit = [latex] \frac {45}{4} [/latex], Sujit = [latex] \frac {45}{4} \times \frac {4}{5}[/latex] = 9
therefore, Ratio of their work = 5 : 4
therefore, Required key depressions per hour a day = [latex]\frac {5}{9} \times 576000 \times \frac {1}{4} \times \frac {1}{5}[/latex] = 16000