Time and work🌹

Man's 1 day work --->1/40 Woman's 1 day work ----> 1/120 Child's 1 day work ----> 1/240 50% of the work is done by Man and 25% each by Woman and Child. Hence, Man's 1 day work ----> 1/20 Woman's 1 day work ----> 1/30 Child's 1 day work ----> 1/60 Total work done in 1 day---> 1/10 10 days needed to finish the work.

Days.          Effi..        contribution in total work P ==10-----          2y------4y Q==3x-----           5a------10a=8y/3 R==20-----           y------4y S==5x-----3a T====20--y P,Q,R,S===55% 45%===9y 55%==11y 4y+8y/3+4y+?=11y ?=y/3 a=8y/30==4y/15 P=2y--------y Q=4y/3-----2y/3 S=4y/5-----2y/5 P'+Q'+R'=31y/15 Total work=20y 60%==20*0.6*15/31==180/31

No. of students is decreasing by 2 everyday and the number of days taken is 15, hence no of students on 8th day is average of the sum of no. of students who worked for 15 days... Let that be x, hence 15x= N*10 x= 2/3*N N has to be a multiple of 3 and x must be an even number only option D satisfies that Or 10x=x+x-2+....x-28 10x=15x-2(14*15)/2 210=5x x=42

m/w = 150/100 = 3/2 tw = 300 if head. m = 3 ; w = 2*1.5 = 3 if tail m = 1 ; w = 1 minimum days = 300/6 = 50 days maximum days = 300/2 = 150 days possibile number of days = 50,52,...,150 total = 51 less than or equal to 90 days ttl = 21 21/51 = 7/17

100x*4--400x 7 days ---2--4---6-----(3 left) 3---5---7----(2 added) 1--100x 2--100x-3 3--100x-3+2 4--100x-3+2-3 5--100x-3+2-3+2 6--100x-3+2-3+2-3 7--100x-3+2-3+2-3+2 Means 700x-36+18=400x 100x= 6

RS.        .   VS 56/3------>200/9          200*7 75-------------->63 S:v=4:5---->5:4(Eff) V=28, S=35, R=40 P*918/43+28*875/43=1400 Solving P~38.9 B=====> 1400/40-11=24(days) Efficiency=1400/24=58.3 Total efficiency= 35+28+40+38.9+58.3~200 1400/200=7 days

36. 48. 42 1008 28. 21. 24 52*6=====312 Remaining===1008-312=696 10*52=======520 696-520======176 176/21=====8 8/21 min

A, B and C can fill the tank in 36, 48 and 42 min respectively. A and C could fill the tank in 6 min and then A and C stopped. Then B started to fill the tank, It fills the tank for some min and again A and C started 10 min before filling the tank. For how long B opened to fill the tank?   7 7/20 min   8 8/21 min   8 9/20 min   6 6/17 min   None of these

Anyone explain this question , please

Anyone explain this question , please

Rus+ prk+ maru---10 days Prak+ ruhi--x-3 days Umesh--2x days Vish+ siya +ruhi---16 days Maruti +umesh---17.5 days Eff--visn. Siya 3. 4 Eff--prak. Maru. Rud 5. 4. 3 Total work done--12×10=120 days Prak---24 days Rud--40 days Maru---30 days Vish+siya+Ru---16--7.5 3. 4. 0.5 Vish---120/3=40 days Siya---120/4=30 days Ru---0.5---240 days Umesh--1/17.5-1/30 ---42 days