1. A laborer was appointed by a contractor on the condition he would be paid Rs 150 for each day of his work but would be, fined a the rate of Rs 30 per day for his absent. After 20 days, the contractor paid the laborer’s 2820. Find the number of days he worked:
A. 13 days
B. 19 days
C. 5 days
D. 12 days
E. None of these
Answer: Option B
Explanation: Let the required number of days = x days
So, 150x- (20-x)30 = 2820
x=19 days
2. In the beginning, Ram works at a rate such that he can finish a piece of work in 24 hrs, but he only works at this rate for 16 hrs. After that, he works at a rate such that he can do the whole work in 18 hrs. If Ram is to finish this work at a stretch, how many hours will he take to finish this work?
A. 12 hrs
B. 18 hrs
C. 11[latex]\frac{50}{3}[/latex]
D. 15 hrs
E. 22 hrs
Answer: Option E
Explanation: Ram’s 16 hr work = [latex]\frac{16}{24}[/latex] =[latex]\frac{60 × 70}{(60 + 70)}[/latex]. Remaining work = 1 – [latex]\frac{2}{3}[/latex] = [latex]\frac{1}{3}[/latex].
Using work and time formula: This will be completed in [latex]\frac{2}{3}[/latex] × 18 i.e. 6 hrs.
So, total time taken to complete work = 16 + 6= 22 hrs.
3. A can do a piece of work in 10 days, and B can do the same work in 20 days. With the help of C, they finished the work in 4 days. C can do the work in how many days, working alone?
A. 5 days
B. 10 days
C. 15 days
D. 20 days
E. 25 days
Answer: Option A
Explanation: Their combined 4 day work = 4([latex]\frac{1}{10}[/latex] + [latex]\frac{1}{15}[/latex]) = [latex]\frac{12}{20}[/latex] = [latex]\frac{3}{5}[/latex].
Remaining work = 1 – [latex]\frac{3}{5}[/latex] = [latex]\frac{2}{5}[/latex].
This means C did [latex]\frac{2}{5}[/latex] work in 4 days, hence he can finish the complete work in [latex]\frac{5}{2}[/latex] × 4 = 10 days.
4. Ajay and Vijay undertake to do a piece of work for Rs. 480. Ajay alone can do it in 75 days while Vijay alone can do it in 40 days. With the help of Pradeep, they finish the work in 25 days. How much should Pradeep get for his work?
A. Rs. 40
B. Rs. 20
C. Rs. 360
D. Rs. 100
E. Rs. 60
Answer: Option B
Explanation: In 24 days, they would have done [latex]\frac{1}{3}[/latex] and [latex]\frac{5}{8}[/latex] of the work.
The remaining work is 1 – ([latex]\frac{1}{3}[/latex] + [latex]\frac{5}{8}[/latex]) = [latex]\frac{1}{24}[/latex].
This means Pradeep has done [latex]\frac{1}{24}[/latex]th of the work, so he should be paid [latex]\frac{1}{24}[/latex]th of the amount i.e. 480 × [latex]\frac{1}{24}[/latex] = Rs. 20 is the answer.
5. Daku and Tamatar can do a piece of work in 70 and 60 days respectively. They began the work together, but Daku leaves after some days and Tamatar finished the remaining work in 47 days. After how many days did Daku leave?
A. 14 days
B. 16 days
C. 18 days
D. 10 days
E. 7 days
Answer: Option E
Explanation: Tamatar would have done [latex]\frac{47}{60}[/latex] work in 47 days. The remaining work i.e. [latex]\frac{13}{60}[/latex] must have been done by Daku and Tamatar together. They can do the whole work in [latex]\frac{60 × 70}{(60 + 70)}[/latex] = 60 × [latex]\frac{70}{130}[/latex] = [latex]\frac{420}{13}[/latex] days.
So, they would have done [latex]\frac{13}{60}[/latex] work in [latex]\frac{420}{13}[/latex] × [latex]\frac{13}{60}[/latex] = 7 days. Therefore, Daku left work after 7 days.