Its an aptitude question. please solve it. its answers is 7 and half hour (it can be wrong, but very less chance). But my answer is 6 and Quarter hour. plz give a solution with all the steps u taken to solve it.
2007-07-31 10:23:27 · 7 answers · asked by Lolla 2 in Science & Mathematics ➔ Mathematics
If you still assume that they will work evenly throughout for 20 days, then your answer (6.75 hrs/day) is correct. Simply multiply 9 by 3/4. Because the number of days did not change. It may be that the number of days may have been changed.
The answer 7.5 hours will mean that they worked for 18 days. ©
30*9*20 = 40*X*7.5 ------- X = 18.
2007-07-31 10:31:36 · answer #1 · answered by Alam Ko Iyan 7 · 0⤊ 0⤋
I looked at Kenneth H's reasoning, and it looked correct. A total of 5400 hrs worth of work was performed.
If the correct answer was 7.5 hrs/day, the total amount of work performed would be:
40 x 20 x 7.5 = 6000 hrs
This proves 7.5 is NOT the correct answer!
You may have copied down the problem wrong. It so happens that 7.5 is 5/6 of 9, so there is a relationship between those numbers. If the answer 7.5 hrs/day is correct, this means a total of 36 men, not 40, performed the job.
Check the problem and get back to us please.
2007-07-31 10:51:03 · answer #2 · answered by whabtbob 6 · 0⤊ 0⤋
time is directly proportional to the amount of labor .
in man hours :
30 * 20 * 9 = 600 * 9 = 5400 hours of work
5400/ 40 = 135 hours per man
135 /9 = 15 days @ 9 hour days.
your question though is how many hours a day do they work
so assume finish in 20 days
5400 man hours / 20 days = 270 man hours per day required
270 / 40 = 6.75 hours per day
2007-07-31 10:42:44 · answer #3 · answered by mark 6 · 0⤊ 0⤋
30 =20 days and 9 hours =20*9=180
=180*30=5400 hours all together
40 men? =5400/40=135 hours
=135/20= 6.75 hours a day
2007-07-31 10:33:59 · answer #4 · answered by flicka 3 · 0⤊ 0⤋
Total hrs spent,while 30 men worked
= 30*20*9
so if 40 men work,we have=30*20*9/20*40
=6.75 hrs/day
2007-07-31 11:55:14 · answer #5 · answered by MAHAANIM07 4 · 0⤊ 0⤋
total manhours to complete job =
30*20*9=5400 manhours
5400/20=270 manhours per day
270/40=6.75
2007-07-31 10:29:54 · answer #6 · answered by Kenneth H 3 · 0⤊ 0⤋
9 hours a day.
2007-07-31 10:39:30 · answer #7 · answered by meetoo 2 · 0⤊ 1⤋