5. Jack can till a garden in 8 hours. Jill can till the same garden in 6 hours. Working together, how long (in hours) would it take to till this garden? (Express your answer to the nearest tenth of an hour.)
2007-06-12 10:48:35 · 12 answers · asked by T P 2 in Science & Mathematics ➔ Mathematics
Use product over sum which would be
8 * 6 / 14 = 48/14 = 3.4 hours
2007-06-12 10:51:58 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Jack = 8 hours
in 1 hour Jack tills 1/8 from the garden
Jill = 6 hours
in one hour Jill tills 1/6 from the garden
Together. they till 1/8 + 1/6 in one hour = 3/24 + 4/24 = 7/24 hour
The whole garden will take them 24/7 hours = 3.43 hours =
3 hours, 25 minutes and 47 seconds plus a fraction of second.
2007-06-12 10:53:52 · answer #2 · answered by Anonymous · 0⤊ 1⤋
Let area of garden be X
In 1 hour Jack tills X/8
in 1 hour Jill tills X/6
Total in 1 hour = X/8 + X/6 = 3X/24 + 4X/24
Total in 1 hour = 7X/24
7X/24---> 1 hour
X<---> 24/7 hours = 3.4 hours (to 1 dec. place)
2007-06-12 21:38:30 · answer #3 · answered by Como 7 · 0⤊ 0⤋
Jack will take 8 hours because he's drinking beer. Jill can get it done in 6 hours because she has to cook supper, do the laundry, get kids in the bath and get em in bed. Really busy, no time to waiste.
If they work together...the garden won't get done at all. Because Jack's drinking and wants to work on Jill. Jill gives in to the old man and they get naked and make another kid. No garden!
Seriously, Jack wants to till Jill's garden. Only one tiller. Jack's still got beer and Jill needs to get to supper. Only time for a quicky...
2007-06-12 11:06:45 · answer #4 · answered by dearly departed 2 · 0⤊ 0⤋
think of it this way, jack can till 1/8 of a garden in 1 hour and jill can till 1/6th of a garden in 1 hour, so in 1 hour, they both till 7/24 of a garden, so divide 1 by 7/24 and you get your answer, which is about 3.42 hours
2007-06-12 10:52:39 · answer #5 · answered by Tim J 2 · 0⤊ 1⤋
the rate of Jack in 1 hour is 1/8
the rate of Jill in 1 hour is 1/6
let t be the time they work togethr
1/8 t + 1/6 t = 1
7/24 t = 1
t = 3.43 hour
2007-06-12 10:55:14 · answer #6 · answered by 7 · 1⤊ 1⤋
2x + 2y = 20 using the simultaneous approach 2x - 2y = 4 ____________ 4x = 24 ( divide by 4) x = 6 replace x in between both equations 2x + 2y = 20 2 (6) + 2y = 20 12 +2y = 20 2y = 20 - 12 2y = 8 (divide by 2) y = 4 answer : X = 6 , Y = 4
2016-11-23 15:17:18 · answer #7 · answered by ? 4 · 0⤊ 0⤋
8*6/(8+6) = 48/14 = 3.4 hours
2007-06-12 10:59:49 · answer #8 · answered by ironduke8159 7 · 0⤊ 0⤋
1/(1/8+1/6)=...
2007-06-12 10:51:11 · answer #9 · answered by A tiger from Wuhu 1 · 0⤊ 1⤋
1/8+1/6=3/24+4/24=7/24
1/(7/24)=24/7=3r3/7
2007-06-12 10:59:12 · answer #10 · answered by Anonymous · 0⤊ 1⤋