Work-Rate ProblemSince the time taken by the four friends to complete the same task individually is 1, 2, 3 and 4 days, respectively so it will be easier to solve the problem is work done is taken as a LCM of (1,2,3,4) * Sum of ratio (1,2,3,4)= 12 * 10 = 120
Using Rate * Time = Work done we can find rate of P,Q,R,S
Calculate RateLet rate of P,Q,R,S be P,Q,R,S respectively
P * time = work done
=> P * 1 = 120 => P = \(\frac{120}{1}\) = 120
Similarly, Q = \(\frac{120}{2}\) = 60
R = \(\frac{120}{3}\) = 40
S = \(\frac{120}{4}\) = 30
Calculate WorkWork done by each of them is in the ratio 1:2:3:4, respectively => it is in the ratio \(\frac{1}{10}\):\(\frac{2}{10}\):\(\frac{3}{10}\):\(\frac{4}{10}\)
=> Actual work done by P,Q,R,S can be calculated by multiplying total work (120) by these fractions
=> Work done by P = \(\frac{1}{10}\) * 120 = 12
=> Work done by Q = \(\frac{2}{10}\) * 120 = 24
=> Work done by R = \(\frac{3}{10}\) * 120 = 36
=> Work done by S = \(\frac{4}{10}\) * 120 = 48
Calculate TimeTime taken by all of them to finish the work in sequence (one after the other ) = Time taken by each one of them to finish their part of work
= Time Taken by P + Time Taken by Q + Time Taken by R + Time Taken by S
= \(\frac{12}{120}\) + \(\frac{24}{60}\) + \(\frac{36}{40}\) + \(\frac{48}{30}\)
= \(\frac{12}{120}\) + \(\frac{48}{120}\) + \(\frac{108}{120}\) + \(\frac{192}{120}\)
= \(\frac{360}{120}\) = 3 days
So,
Answer will be AHope it helps!
Watch the following video to learn How to Solve Work Rate Problems