1. A completes a work in 12 days and B complete the same work in 24 days. If both of them work together, then the number of days required to complete the work will be
A. 8 days
B. 6 days
C. 7 days
D. 5 days
Answer: Option: A
Explanation:
If A can complete a work in x days and B can complete the same work in y days, then, both
of them together can complete the work in [latex]\frac{xy}{x + y}[/latex] days
Therefore, here, the required number of days = 12 × [latex]\frac{24}{36}[/latex] = 8 days.
2. If 3 persons can do 3 times of a particular work in 3 days, then, 7 persons can do 7 times of that work in
A. 7 days
B. 6 days
C. 4 days
D. 3 days
Answer: Option: D
Explanation:
That is, 1 person can do one time of the work in 3 days.
Therefore, 7 persons can do 7 times work in the same 3 days itself.
3. Mangala completes a piece of work in 10 days, Raju completes the same work in 40 days. If both of them work together, then the number of days required to complete the work is
A. 15 days
B. 10 days
C. 9 days
D. 8 days
Answer: Option: D
Explanation:
If A can complete a work in x days and B can complete the same work in y days, then, both
of them together can complete the work in [latex]\frac{xy}{x + y}[/latex] days.
That is, the required No. of days = 10 × [latex]\frac{40}{50}[/latex] = 8 days.
4. 12 men work 8 hours per day to complete the work in 10 days. To complete the same work in 8 days, working 15 hours a day, the number of men required
A. 4 days
B. 5 days
C. 6 days
D. 8 days
Answer: Option: D
Explanation:
That is, 1 work done = 12 × 8 × 10
Then, 12 8 × 10 = ? × 15 × 8
? (i.e. No. of men required) = 12 × 8 × [latex]\frac{10}{15}[/latex] × 10 = 8 days.
5. If 5 people undertook a piece of construction work and finished half the job in 15 days. If two people drop out, then the job will be completed in
A. 25 days
B. 20 days
C. 15 days
D. 10 days
Answer: Option: A
Explanation:
That is, half the work done = 5 × 15 × [latex]\frac{1}{2}[/latex]
Then, 5 × 15 × [latex]\frac{1}{2}[/latex] = 3 × ? × [latex]\frac{1}{2}[/latex]
i.e. 5 × 15 = 3 × ?
therefore, ? (No. days required) = 5 × [latex]\frac{15}{3}[/latex] = 25 days.