trying to study for test and I stink in algebra... can you explain how to solve this problem?
2007-08-27 01:01:29 · 11 answers · asked by sskstru 4 in Science & Mathematics ➔ Mathematics
Let area to be painted = X units ²
Sally`s rate of work = X / 4 units² / hour
Jay`s rate of work = X / 6 units² / hour
In 1 hour they paint:-
X / 4 + X / 6 units²
= 5X / 12 units²
Time taken when working together is:-
X / (5X/12) hours
= 12 / 5 hours
= 2 2/5 hours
= 2 hours 24 minutes
2007-08-27 07:48:23 · answer #1 · answered by Como 7 · 1⤊ 0⤋
Let x = no. of hours to paint the house together, x/4 = the portion that Sally can paint, x/6 = portion that Jay can paint.
Equation:
x/4 + x/6 = 1
Find the least common denominator of 4 and 6 and that is 12:
3x/12 + 2x/12 = 1
5x/12 = 1
5x = 12
x = 12/5
Answer: 2 2/5 hrs or 2 hrs & 24 min
Proof:
100%([2 2/5] / 4) + 100%([2 2/5] / 6) = 100%
100%(3/5) + 100%(2/5) = 100%
60% + 40% = 100%
2007-08-27 08:18:34 · answer #2 · answered by Jun Agruda 7 · 3⤊ 0⤋
Let x = no. of hours to paint the house together, x/4 = the portion that Sally can paint, x/6 = portion that Jay can paint.
Equation:
x/4 + x/6 = 1
Find the least common denominator of 4 and 6 and that is 12:
3x/12 + 2x/12 = 1
5x/12 = 1
5x = 12
x = 12/5
Answer: 2 2/5 hrs or 2 hrs & 24 min
2007-08-27 08:09:14 · answer #3 · answered by Jamie 3 · 1⤊ 0⤋
Sally paints full house in 4 hrs => 1/4 in 1hr
Jay paints full house in 6 hrs => 1/6 in 1 hr
Therefore together they will paint (1/4 + 1/6) house in 1 hr
Or (3/12 + 2/12) house in 1hr
Or 5/12 house in 1 hr
Time they will take to paint full house is given by 1/rate
= 1/[5/12 per hr]
= 12/5 hr
= 2 hours 24 minutes.
2007-08-27 08:15:47 · answer #4 · answered by sv 7 · 0⤊ 0⤋
Each hour, Sally gets 1/4 of the house done and Jay gets 1/6 of the house done.
So, you need to find out how many hours (x) it takes to complete the house:
1/4 * x + 1/6 * x = 1
x + 4/6 * x = 4
6x + 4x = 24
10x = 24
x = 2.4
So, it will take 2.4 hours to complete the house if both are working on it.
2007-08-27 08:13:55 · answer #5 · answered by Jeremiah F 3 · 0⤊ 0⤋
sally one hour can paint 1/4 of the house.
Jay can paint 1/6 of the house in an hour.
Both work together can work 1/4+1/6 = 5/12 of the house .
therefore it took the whose house divide by 5/12 portion of the house per hour, ie 12/5 = 2.4 hour.
2007-08-27 08:17:13 · answer #6 · answered by Tee 2 · 0⤊ 0⤋
1/4x + 1/6x = 1
Multiply both sides of the equation by 12
12(1/4x) + 12(1/6x) = 12(1)
3x + 2x = 12
5x = 12
Divide both sides of the equation by 5
5x/5 = 12/5
x = 12/5
x = 2 2/5 hours
- - - - - -
Find minutes
Multiply 2/5 times 60
2/5(60) =
120/5 = 24 Minutes
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It will take Sally and Jay 2 hours and 24 minutes to paint the house.
- - - - - - - -s-
2007-08-27 08:41:47 · answer #7 · answered by SAMUEL D 7 · 1⤊ 0⤋
let the time taken by thenm together be t then,
Sally does 1/4 of the work per unit time, Jay does 1/6 per unit time & together they do 1/t per unit time
so,
1/4+1/6=1/t
5/12=1/t
so t=12/5=2.4 hours
2007-08-27 08:12:02 · answer #8 · answered by shubham_nath 3 · 0⤊ 1⤋
It all depends on whether or not Sally and Jay are union painters!
2007-08-27 08:13:32 · answer #9 · answered by auntcookie84 6 · 0⤊ 0⤋
x / 6 + x /4 = 1
4 x + 6 x = 24
10 x = 24
x = 2.4 hours
2007-08-27 08:11:16 · answer #10 · answered by CPUcate 6 · 1⤊ 1⤋