6 Machines, each working at the same constant rate together can complete a certain job in 12 days, How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days? Please provide explaination!
2006-09-17 20:56:03 · 5 answers · asked by banana219 1 in Science & Mathematics ➔ Mathematics
this is for GMAT?
Total job = 12 days X 6 machines = 72 machine days
To finish in 8 days: 72 machines days/8 days = 9 machines
therefore, 3 additional machines
2006-09-17 21:03:29 · answer #1 · answered by Anonymous · 1⤊ 0⤋
It takes a total of 6 x 12 = 72 machine days to complete the job. To do the job in 8 days takes 72/8 machines = 9 machines = 9-6 = 3 extra machines.
2006-09-17 22:19:16 · answer #2 · answered by uselessadvice 4 · 0⤊ 0⤋
total machine required = 12 days / 8 days x 6 machines = 9 machines.
you need 9-6 = 3 additional machines
2006-09-17 21:23:35 · answer #3 · answered by Antila 2 · 0⤊ 0⤋
Think about what would happen if you double the number of machines. Twice as many machines would finish the same work in half the time. What about if you had half as many machines. This would double the amount of time it takes.
You want to decrease the time taken by 2/3. (2/3 * 12 = 8)
multiply the number of machines by 3/2.
6 * 3/2 = 9
You already have 6 machines so you need 3 more
The answer is 3
2006-09-17 21:04:50 · answer #4 · answered by Demiurge42 7 · 0⤊ 0⤋
3 additional machines.
2006-09-17 21:05:56 · answer #5 · answered by King Midas 6 · 0⤊ 0⤋