Math Problem 3! Help Appreciated

[Dunzo]

Hey guys! I have a problem of the week for my math class I haven't really looked at it but if you all could help it would be greatly appreciated! If you agree with one person's answer please post saying so. Thanks!

Working Together:

Huck can build a raft in 5 hours. Jim can do the same job by himself in 6 hours. They decide to work together, but they stop to talk and sometimes they get in each other's way. Assume that each boy's productivity (building rate) decreases by the same percent. If they complete the job in 3 1/2 hours, what is the percent decrease in the boys' building rates? Answer may be rounded to the nearest whole percent.

[xyax]

Ok, i can understand making 1 thread or maybe 2, but this is ur 3rd time, this is not a math forum.

[X117]

Ok, i can understand making 1 thread or maybe 2, but this is ur 3rd time, this is not a math forum.

Oh right... we all forgot that you answered both of the past problems and now your 2 last brain cells are dead now :(

[xHellsx]

Forums are about Community, community is about helping one another! Therefore he can do this if he likes :)

[Dunzo]

cool bro ill just wait for havokd (:

[BldMx]

I think its 28% but not sure..

[HavokD]

cool bro ill just wait for havokd (:

Im on it, tho I have to be honest Ive never solved anything like this =/, I would appreciate if BldMx told us how he got that answer and I will check it tomorrow (I have stuff to do for this night =/)

[Random-j]

Found this:

1/5 + 1/6 = 11/30

30/11 = 2 8/11

Decrease = 3 1/2 - 2 8/11 = 7/2 - 30/11 = 17/22

% decrease 17/22/ 7/2 X 100 = 17 X 2 X 100
-----------------------
22 X 7

= 1700/ 77 = 22.08 %

[Dunzo]

thanks anyone know if thats right?^

[Random-j]

thanks anyone know if thats right?^

If you cant google it it doesnt exist.

[Chenson]

Jim and Huck are working together, so the average time to make a raft if they where only one person would be:

6 + 5 / 2 = 5,5

But they are two guys so: 5,5 / 2 = 2,75 average.

Then you do the proportion:

2,75 = 100%
3,5 = x

x = 100*3,5/2,75
x = 127,27 %

So 27,27% over the time they where supposed to finish. The nearest whole percent is 27%.

[HavokD]

Jim and Huck are working together, so the average time to make a raft if they where only one person would be:

6 + 5 / 2 = 5,5

But they are two guys so: 5,5 / 2 = 2,75 average.

Then you do the proportion:

2,75 = 100%
3,5 = x

x = 100*3,5/2,75
x = 127,27 %

So 27,27% over the time they where supposed to finish. The nearest whole percent is 27%.

I will take part of his answer, but I will make a few changes (I expect my answer to be the correct answer).

In my stupid way of viewing things, the proportion should be
3.75 = 100%
2.75 = x

Why? because we need the decrease in performance, the way we do this is by taking the 3.75 hours that took building the raft up, and saying that our 100%.

Now we want to know what would have happened if they worked on an ideally manner. Thats why we calculate 2.75= X

That yields x= 2.75*100/3.5= 78.57

So we just do 100- 78.57= 21.43

Rounded down is 21%. And thats our decrease in performance.

Note: I cant garantee this is 100% correct, it can either be this answer or Chenson's, I hope someone can give the final word on this.

[BldMx]

Jim and Huck are working together, so the average time to make a raft if they where only one person would be:

6 + 5 / 2 = 5,5

But they are two guys so: 5,5 / 2 = 2,75 average.

Then you do the proportion:

2,75 = 100%
3,5 = x

x = 100*3,5/2,75
x = 127,27 %

So 27,27% over the time they where supposed to finish. The nearest whole percent is 27%.

This is what I did.

[Dunzo]

thanks for the replies people ill have one up again in two days (:

[xyax]

Ask ur math teacher for help (:

[HavokD]

Found this:

1/5 + 1/6 = 11/30

30/11 = 2 8/11

Decrease = 3 1/2 - 2 8/11 = 7/2 - 30/11 = 17/22

% decrease 17/22/ 7/2 X 100 = 17 X 2 X 100
-----------------------
22 X 7

= 1700/ 77 = 22.08 %

Hey Dunzo, I answered the problem with help from a great teacher, and THIS is the real answer. I hope you get it right on time!