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Saturday, 27 December 2014

Time and Work - Complex Problems (Part-2)

1)A and B undertake to do a piece of workfor Rs 600.A alone can do it in 6 days while B alone can do it in 8 days. With the help of C, they can finish it in 3 days, Find the share of each?
a.Rs 50
b.Rs 75
c.Rs.100
d.Rs.150


2)A can do a piece of work in 80 days. He works at it for 10 days & then B alone finishes the remaining work in 42 days. In how much time will A and B, working together, finish the work?
a.30 days
b.40 days
c.50 days
d.60 days


3)P,Q and R are three typists who working simultaneously can type 216 pages in 4 hours In one hour , R can type as many pages more than Q as Q can type more than P. During a period of five hours, R can type as many pages as P can during seven hours. How many pages does each of them type per hour?
a.x=15,y=18, and z=21
b.x=15,y=21, and z=21
c.x=18,y=18, and z=21
d. x=15,y=18, and z=15


4)Ronald and Elan are working on an assignment. Ronald takes 6 hours to type 32 pages on a computer, while Elan takes 5 hours to type 40 pages. How much time will they take, working together on two different computers to type an assignment of 110 pages?
a.6 hours
b.8 hours
c.10 hours
d. 12 hours


5)Two workers A and B are engaged to do a work. A working alone takes 8 hours more to complete the job than if both working together. If B worked alone, he would need 4 1/2 hours more to compete the job than they both working together. What time would they take to do the work together.
a.3 days
b.4 days
c.5days
d.6 days

6)A and B can do a work in12 days, B and C in 15 days, C and A in 20 days. If A,B and C work together, they will complete the work in how many days?
a.8 days
b.5 days
c.10 days
d.12 days



7)A and B can do a work in 8 days, B and C can do the same wor in 12 days. A,B and C together can finish it in 6 days. A and C together will do it in how many days?
a.8 days
b.5 days
c.10 days
d.12 days


8)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 10 days and C alone in 50 days, then B alone could do it in how many days?
a.80 days
b.50 days
c.25 days
d.12 days


9) A is thrice as good a workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in:
a.45 days
b.45/2 days
c.20 days
d.12 days

                                                           
10) A can do a piece of work in 80 days. He works at it for 10 days and then B alone finishes the remaining work in 42 days. In how much time will A&B, working together, finish the work?
a.80 days
b.30 days
c.20 days
d.12 days

Answers :

Sol 1: C's one day's work=(1/3)-(1/6+1/8)=1/24
             Therefore, A:B:C= Ratio of their one day’s work=1/6:1/8:1/24=4:3:1
             A's share=Rs (600*4/8)=300
             B's share= Rs (600*3/8)=225
             C's share=Rs[600-(300+225)]=Rs 75

Sol 2:     Work done by A in 10 days=10/80=1/8
             Remaining work=(1-(1/8))=7/8
             Now, work will be done by B in 42 days.
             Whole work will be done by B in (42*8/7)=48 days
             Therefore, A's one day's work=1/80
             B’s one day's work=1/48
             (A+B)'s one day's work=1/80+1/48=8/240=1/30
             Hence, both will finish the work in 30 days.

Sol 3 :Let the number of pages typed in one hour by P, Q and R be x,y and z
    respectively
             Then x+y+z=216/4=54 ---------------1
             z-y=y-x => 2y=x+z -----------2
             5z=7x => x=5x/7 ---------------3
             Solving 1,2 and 3 we get x=15,y=18, and z=21

Sol 4:         Number of pages typed by Ronald in one hour=32/6=16/3
             Number of pages typed by Elan in one hour=40/5=8
             Number of pages typed by both in one hour=((16/3)+8)=40/3
             Time taken by both to type 110 pages=110*3/40=8 hours.

Sol 5:         (1/(x+8))+(1/(x+(9/2)))=1/x
           =>(1/(x+8))+(2/(2x+9))=1/x
           => x(4x+25)=(x+8)(2x+9)
           => 2x2 =72
           => x2 = 36
           => x=6
              Therefore, A and B together can do the work in 6 days.

 Sol 6:          (A+B)'s one day's work=1/12;
              (B+C)'s one day's work=1/15;
              (A+C)'s one day's work=1/20;
               Adding we get 2(A+B+C)'s one day's work=1/12+1/15+1/20=12/60=1/5
              (A+B+C)'s one day work=1/10
              So, A,B,and C together can complete the work in 10 days.

Sol 7:          (A+B+C)'s one day's work=1/6;
              (A+B)'s one day's work=1/8;
              (B+C)'s one day's work=1/12;
              (A+C)'s one day's work=2(A+B+C)'s one day's work-((A+B)'s one day
                                      work+(B+C)'s one day work)
                                   = (2/6)-(1/8+1/12)
                                   =(1/3)- (5/24)
                                   =3/24
                                   =1/8
               So, A and C together will do the work in 8 days.

Sol 8:        (A+B)'s one day's work=1/10;
            C's one day's work=1/50
            (A+B+C)'s one day's work=(1/10+1/50)=6/50=3/25
            Also, A's one day's work=(B+C)’s one day's work
            From i and ii ,we get :2*(A's one day's work)=3/25
         => A's one day's work=3/50
            B's one day’s work=(1/10-3/50)
                             =2/50
                             =1/25
            B alone could complete the work in 25 days.

Sol 9:        Ratio of times taken by A and B=1:3.
            If difference of time is 2 days , B takes 3 days
            If difference of time is 60 days, B takes (3*60/2)=90 days
            So, A takes 30 days to do the work=1/90
            A's one day's work=1/30;
            B's one day's work=1/90;
            (A+B)'s one day's work=1/30+1/90=4/90=2/45
            Therefore, A&B together can do the work in 45/2days

Sol 10:           Work Done by A n 10 days =10/80=1/8
               Remaining work =1-1/8=7/8
               Now 7/8 work is done by B in 42 days
               Whole work will be done by B in 42*8/7= 48 days
            => A's one day's work =1/80 and
               B's one day's work =1/48
               (A+B)'s one day's work = 1/80+1/48 = 8/240 = 1/30
               Hence both will finish the work in 30 days.


Click Here for the Time and Work (Part-1)
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