how long should it take him to paint a wall that measures 16 feet by 18 feet?

lev888 said:
Yes. And if R=W/T, what is T?
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The amount of work done (W) is the product of the rate of work (r) and the time spent working (t)
t = w/r
if t is not time here then I really do not know what that t is, in this formula, the one you have given me.
 
eddy2017 said:
The amount of work done (W) is the product of the rate of work (r) and the time spent working (t)
t = w/r
if t is not time here then I really do not know what that t is, in this formula, the one you have given me.
Click to expand...
Yes, now it's correct. Before you wrote t=w*r.
You should do more exercises on this type of symbol manipulation, otherwise you'll have a difficult time using formulas and solving equations.
So, t = w/r. If we plug in correct values we'll be all set. Do we know w or r?
 
Ye
lev888 said:
Yes, now it's correct. Before you wrote t=w*r.
You should do more exercises on this type of symbol manipulation, otherwise you'll have a difficult time using formulas and solving equations.
So, t = w/r. If we plug in correct values we'll be all set. Do we know w or r?
Click to expand...
Yes, I do
W= 288ft² ( the amount of ft to be painted)
t = 3 hours
 
eddy2017 said:
Sorry Mr lev . I had to stop last night.
We know the rate of speed is 3 hours.
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No problem.
Can you point me where in the problem it says that "rate of speed is 3 hours" for the second wall?
 
lev888 said:
No problem.
Can you point me where in the problem it says that "rate of speed is 3 hours" for the second wall?
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It says that he would be working at the same speed, oh but , but no there is no info about what the rate of speed is. No, they are not giving it. It is an unknown
 
We have the amount if work done but we need the rate of speed and the time.
 
eddy2017 said:
We have the amount if work done but we need the rate of speed and the time.
Click to expand...
I know that it took him 3 hours to paint the first wall so that my be a rate : 1 wall per 3hrs or the amount of square feet in the wall per hour = 240 per 3hrs.
 
eddy2017 said:
I know that it took him 3 hours to paint the first wall so that my be a rate : 1 wall per 3hrs or the amount of square feet in the wall per hour = 240 per 3hrs.
Click to expand...
Let's do everything systematically.
First of all, please look at your answers critically: does "rate of speed is 3 hours" make sense? No. rate is measured in units of something per unit of time. This is not a competition, you don't get bonus points for fast answers - take your time to review them. Critically.

So, you are right, the rate for the second wall is not immediately known.
What do we do next? Exactly the same thing as in the first step, when we addressed the 'main' unknown'.
We identified the question - what is the rate for the second wall.
Then we write down the relationship that connects the rate to other quantities in the problem (work and time):
rate = work/time

We don't need to rearrange it since rate is already on the left hand side.
Do we have work and time specified in the problem that we can plug into this expression to calculate the rate?
 
lev888 said:
Let's do everything systematically.
First of all, please look at your answers critically: does "rate of speed is 3 hours" make sense? No. rate is measured in units of something per unit of time. This is not a competition, you don't get bonus points for fast answers - take your time to review them. Critically.

So, you are right, the rate for the second wall is not immediately known.
What do we do next? Exactly the same thing as in the first step, when we addressed the 'main' unknown'.
We identified the question - what is the rate for the second wall.
Then we write down the relationship that connects the rate to other quantities in the problem (work and time):
rate = work/time

We don't need to rearrange it since rate is already on the left hand side.
Do we have work and time specified in the problem that we can plug into this expression to calculate the rate?
Click to expand...
No, the speed of rate is not 3 hours only. I did this. Let me know what you think.
I know that it took him 3 hours to paint the first wall so that might be a rate : 1 wall per 3hrs or the amount of square feet in the wall per hour = 240 per 3hrs.
I can say that the rate of painting is = 24 * 10 / 3 = 80 ft^2
So he paints 80 ft^2 in 1 hour.
1 hour= 80 ft^2
So,
80 ft^2 /1 hr =16 * 18 ft^2 / xh ( x cos we're trying to find the time needed to paint the second wall.
I will isolate x now
`xh= 16 * 18 ft^2
80ft^2 `
th=3.6 hours to paint the second wall`
 
eddy2017 said:
No, the speed of rate is not 3 hours only. I did this. Let me know what you think.
I know that it took him 3 hours to paint the first wall so that might be a rate : 1 wall per 3hrs or the amount of square feet in the wall per hour = 240 per 3hrs.
I can say that the rate of painting is = 24 * 10 / 3 = 80 ft^2
So he paints 80 ft^2 in 1 hour.
1 hour= 80 ft^2
So,
80 ft^2 /1 hr =16 * 18 ft^2 / xh ( x cos we're trying to find the time needed to paint the second wall.
I will isolate x now
`xh= 16 * 18 ft^2
80ft^2 `
th=3.6 hours to paint the second wall`
Click to expand...
Can you just answer my questions? I understand that you already solved it, but I am trying to show you a more organized approach, that will work for many different problems.
 
lev888 said:
Let's do everything systematically.
First of all, please look at your answers critically: does "rate of speed is 3 hours" make sense? No. rate is measured in units of something per unit of time. This is not a competition, you don't get bonus points for fast answers - take your time to review them. Critically.

So, you are right, the rate for the second wall is not immediately known.
What do we do next? Exactly the same thing as in the first step, when we addressed the 'main' unknown'.
We identified the question - what is the rate for the second wall.
Then we write down the relationship that connects the rate to other quantities in the problem (work and time):
rate = work/time

We don't need to rearrange it since rate is already on the left hand side.
Do we have work and time specified in the problem that we can plug into this expression to calculate the rate?
Click to expand...
rate = work/time
24 * 10 / 3 = 80 ft^2/h ( this is the rate)
80 ft^2/h =16 * 18 ft^2(work to be done)/ xh ( in x time, unknown)
80ft^2/h= 288 ft^2/xh ( solving for x)
xh= 288 ft^2/ 80 ft^2 (ft^2 cancel out)
xh=3.6 the time it will take him to paint the other wall.
 
WOW!, It is so easy with that formula!. More together and organized, yes, sir , it is!. Thanks!.
That is why I could see what units to cancel easily.
 
eddy2017 said:
rate = work/time
24 * 10 / 3 = 80 ft^2/h ( this is the rate)
80 ft^2/h =16 * 18 ft^2(work to be done)/ xh ( in x time, unknown)
80ft^2/h= 288 ft^2/xh ( solving for x)
xh= 288 ft^2/ 80 ft^2 (ft^2 cancel out)
xh=3.6 the time it will take him to paint the other wall.
Click to expand...
Could you just answer my questions?
 
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