1. 12 men complete a work in 9 days. After they have worked for 6 days, 6 more men join them. How many days will they take to complete the remaining work?
A. 2 days
B. 3 days
C. 4 days
D. 5 days
Answer: Option: A
Explanation:
1 man's 1 day work = [latex]\frac{1}{108}[/latex]
12 men's 6 day's work = [latex]\frac{1}{9}[/latex] * 6 = [latex]\frac{2}{3}[/latex]
Remaining work = 1 - [latex]\frac{2}{3}[/latex] = [latex]\frac{1}{3}[/latex]
18 men's 1 day work = 1/108 * 18 = [latex]\frac{1}{6}[/latex]
[latex]\frac{1}{6}[/latex] work is done by them in 1 day.
[latex]\frac{1}{3}[/latex] work is done by them in 6 * [latex]\frac{1}{3}[/latex] = 2 days.
2. A take twice as much time as B or thrice as much time to finish a piece of work. Working together, they can finish the work in 2 days. B can do the work alone in?
A. 4 hours
B. 6 hours
C. 8 hours
D. 12 hours
Answer: Option: B
Explanation:
Suppose A, B and C take x, [latex]\frac{X}{2}[/latex] and [latex]\frac{X}{3}[/latex] respectively to finish the work.
Then, ([latex]\frac{1}{X}[/latex] + [latex]\frac{2}{X}[/latex] + [latex]\frac{3}{X}[/latex]) = 1/2
[latex]\frac{6}{X}[/latex] = [latex]\frac{1}{2}[/latex] => x = 12
So, B takes 6 hours to finish the work.
3. 10 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work?
A. 3
B. 5
C. 7
D. Cannot be determined
Answer: Option: C
Explanation:
1 women's 1 day work = [latex]\frac{1}{70}[/latex]
1 child's 1 day work = [latex]\frac{1}{140}[/latex]
(5 women + 10 children)'s 1 day work
= ([latex]\frac{5}{10}[/latex] + [latex]\frac{10}{40}[/latex]) = (1/14 + [latex]\frac{1}{14}[/latex]) = [latex]\frac{1}{7}[/latex]
5 women and 10 children will complete the work in 7 days.
4. If 12 men and 16 boys can do a piece of work in 5 days; 13 men and 24 boys can do it in 4 days, then the ratio of the daily work done by a man to that of a boy is?
A. 2:1
B. 3:1
C. 3:2
D. 5:4
Answer: Option: A
Explanation:
Let 1 man's 1 day work = x and 1 boy's 1 day work = y.
Then, 12x + 16y = [latex]\frac{1}{5}[/latex] and 13x + 24y = 1/4
Solving these two equations, we get:
x = [latex]\frac{1}{100}[/latex] and y = [latex]\frac{1}{20}[/latex]
Required ratio = x:y = [latex]\frac{1}{100}[/latex] : [latex]\frac{1}{200}[/latex] = 2:1
5. 4 men and 6 women can complete a work in 8 days, while 3 men and 7 women can complete it in 10 days. In how many days will 10 women complete it?
Answer: Option: B
Explanation:
Let 1 man's 1 day work = x and 1 woman's 1 day work = y.
Then, 4x + 6y = [latex]\frac{1}{8}[/latex] and 3x + 7y = [latex]\frac{1}{10}[/latex]
Solving these two equations, we get:
x = [latex]\frac{11}{400}[/latex] and y = [latex]\frac{1}{400}[/latex]
1 woman's 1 day work = ([latex]\frac{1}{400}[/latex] * 10) = [latex]\frac{1}{40}[/latex].
Hence, 10 women will complete the work in 40 days