10%
X filling rate is 1/18 or 4/72 per hour
Y filling rate is 1/24 or 3/72 per hour
Combined as a pair it’s 7/72 in a complete 2 hour alternating sequence
72+ 7/72 =10 sequences = 70/72 on 20 hours, The outstanding balance is just 2/72
So at 20.5 hours with X turn filling is 100% complete with 72/72
Answer: It will take 20.5 hours to completely fill this tank.
Analysis of measured filling process, from X = 42/72 share & from Y = 30/72 share
1
6=1x2x3
24=2x3x4
60=3x4x5
120=4x5x6
210=5x6x7
336=6x7x8
Summation of 301 – summation of 99
=41550
Summation of n=((n*n+1)/2)
To solve this problem, we can break it down into steps:
Step 1: Determine the individual rates of work for A, B, and C.
If A needs 8 days to finish the task, then their work rate is 1/8 of the task per day.
If B needs 12 days to finish the task, then their work rate is 1/12 of the task per day.
If C needs 16 days to finish the task, then their work rate is 1/16 of the task per day.
Step 2: Calculate the combined work rate of A and B.
If A works for 2 days, their contribution will be 2 * (1/8) = 1/4 of the task completed.
If B works until 25% of the job is left for C, then they will complete 75% of the task.
Step 3: Calculate the time it takes for B to complete 75% of the task.
Since B’s work rate is 1/12 of the task per day, it will take B (75%)/(1/12) = 9 days to complete 75% of the task.
Step 4: Calculate the remaining work for C.
If B completes 75% of the task, then the remaining work for C is 100% – 75% = 25% of the task.
Step 5: Calculate the time it takes for C to complete the remaining work.
Since C’s work rate is 1/16 of the task per day, it will take C (25%)/(1/16) = 4 days to complete the remaining 25% of the task.
Step 6: Calculate the total time required.
A worked for 2 days, B worked for 9 days, and C worked for 4 days, totaling 2 + 9 + 4 = 15 days.
Therefore, it will take a total of 15 days for A to work for 2 days, B to work until 25% of the job is left, and C to complete the remaining work.
20
speed of downstream=speed at still water+flow
= 15+5=20
13
( b ) ANGEME
36,20