7
Q:

# Adam and Smith are working on a project. Adam takes 6 hrs to type 36 pages on a computer, while Smith takes 5 hrs to type 40 pages. How much time will they take, working together on two different computers to type a project of 120 pages?

 A) 8 hrs 45 min B) 8 hrs 42 min C) 8 hrs D) 8 hrs 34 min

Answer:   D) 8 hrs 34 min

Explanation:

Number of pages typed by Adam in 1 hour = $\inline \fn_jvn \small \frac{36}{6}$ = 6
Number of pages typed by Smith in 1 hour = $\inline \fn_jvn \small \frac{40}{5}$ = 8
Number of pages typed by both in 1 hour = (6 + 8) = 14
Time taken by both to type 110 pages = (120 * 1/14) = 8 $\inline \fn_jvn \small \frac{4}{7}$ = 8 hrs 34 min.

Q:

A can finish a work in 15 days and B can do the same work in 12 days . B worked for 8 days and left the job .In how many days, A alone can finish the remaining work?

 A) 6 days B) 5 days C) 4 days D) 3 days

Answer & Explanation Answer: B) 5 days

Explanation:

B's 8 days work=$\inline&space;{\color{Black}(\frac{1}{12}\times&space;8&space;)=\frac{2}{3}}$

Reaining work= $\inline&space;{\color{Black}(1-\frac{2}{3})=\frac{1}{3}}$

Now, $\inline&space;{\color{Black}\frac{1}{15}}$ work is done by A in 1 day

$\inline&space;{\color{Black}\therefore&space;}$ $\inline&space;{\color{Black}\frac{1}{3}&space;}$  work is done by A in$\inline&space;{\color{Black}(15\times&space;\frac{1}{3})&space;}$ = 5 days

0 474
Q:

A works twice as fast as B.If  B can complete a work in 18 days independently,the number of days  in which A and B can together finish the work is:

 A) 4 days B) 6 days C) 8 days D) 10 days

Answer & Explanation Answer: B) 6 days

Explanation:

Ratio of rates of working of A and B =2:1. So, ratio of times taken =1:2

$\inline&space;{\color{Black}\therefore&space;}$A's 1 day's work=1/9

B's 1 day's work=1/18

(A+B)'s 1 day's work=$\inline&space;{\color{Black}(\frac{1}{9}&space;+\frac{1}{18})=\frac{3}{18}=\frac{1}{6}&space;}$

so, A and B together can finish the work in 6 days

6 1923
Q:

A can do a certain work in the same time in which B and C together can do it.If A and B together could do it in 20 days and C alone in 60 days ,then B alone could do it in:

 A) 20days B) 40 days C) 50 days D) 60 days

Answer & Explanation Answer: D) 60 days

Explanation:

(A+B)'s 1 day's work=1/20

C's 1 day work=1/60

(A+B+C)'s 1 day's work=$\inline&space;{\color{Black}&space;\left&space;(&space;\frac{1}{20}&space;+&space;\frac{1}{60}\right&space;)=\frac{4}{60}=\frac{1}{15}}$

Also A's 1 day's work =(B+C)'s 1 day's work

$\inline&space;{\color{Black}&space;\therefore&space;}$ we get: 2 * (A's 1 day 's work)=1/15

=>A's 1 day's work=1/30

$\inline&space;{\color{Black}&space;\therefore&space;}$ B's 1 day's work= $\inline&space;{\color{Black}&space;\left&space;(&space;\frac{1}{20}&space;-\frac{1}{30}\right&space;)=\frac{1}{60}}$

So, B alone could do the work in 60 days.

12 4432
Q:

P can complete a work in 12 days working 8 hours a day.Q can complete the same work in 8 days working 10 hours a day. If both p and Q work together,working 8 hours a day,in how many days can they complete the work?

 A) 60/11 B) 61/11 C) 71/11 D) 72/11

Explanation:

P can complete the work in (12 * 8) hrs = 96 hrs

Q can complete the work in (8 * 10) hrs=80 hrs

$\inline&space;{\color{Black}\therefore&space;}$ P's 1 hour work=1/96   and Q's 1 hour work= 1/80

(P+Q)'s 1 hour's work =$\inline&space;{\color{Black}&space;\left&space;(&space;\frac{1}{96}+\frac{1}{80}&space;\right&space;)}$ =$\inline&space;{\color{Black}&space;\frac{11}{480}}$

so both P and Q will finish the work in $\inline&space;{\color{Black}&space;\frac{480}{11}}$ hrs

$\inline&space;{\color{Black}&space;\therefore&space;}$ Number of days of 8 hours each = $\inline&space;{\color{Black}&space;\left&space;(&space;\frac{480}{11}&space;\times&space;\frac{1}{8}\right&space;)=\frac{60}{11}}$

7 2502
Q:

A, B and C can complete a piece of work in 24,6 and 12 days respectively.Working together, they will complete the same work in:

 A) 1/24 days B) 7/24 days C) 24/7 days D) 4 days

(A+B+C)'s 1 day's work =$\inline&space;{\color{Black}\left&space;(&space;\frac{1}{24}+\frac{1}{6}+\frac{1}{12}&space;\right&space;)=\frac{7}{24}}$