Basic Arithmetic Question? (1 Viewer)

[fatima96]

Could you guys help, I don't know what to do here. :/

a river flows at 3 km/h. At what speed must a boat travel in order to make a 35km long trip upstream in 50 minutes? How long will it take the boat to make the return trip downstream? (assuem the boat travels at the same speed travelled upstream).

 

[powlmao]

Is this geometrical application of calculus?

 

[fatima96]

Is this geometrical application of calculus?

No, it's just basic arithmetic lol
I don't really know how to go about this question ...

 

[powlmao]

I am trying to get my head around how to answer it. One sec i will get paper

 

[fatima96]

I am trying to get my head around how to answer it. One sec i will get paper

Thank you very much

 

[powlmao]

I can get it. But i have used logs... So that really isn't arithmetic

 

[powlmao]

The Answer is 45km/hr

 

[powlmao]

Forgot. The river goes at 3km/hr

So boat goes 45km/hr

 

[fatima96]

The Answer is 42km/hr

It is actually 45km/hr I have not done logs yet, still on the prelim course

 

[David_Chen]

Distance= Speed x Time

Speed = Distance/Time


Upstream : Going against the current, so subtract the river flow

(v -3) = 35km / [5/6 hrs]
v = 45km/hr

Downstream: Going with the current, so add river flow

45+3 = 35km/ [ t hours]

solve for t

t = 35 / [48] = 0.729..hours = 0.729 x 60mins = 43 minutes and 45 seconds.

 

[David_Chen]

Forgot. The river goes at 3km/hr

So boat goes 39km/hr

lol newbs

 

[powlmao]

It is actually 45km/hr I have not done logs yet, still on the prelim course

If you add the 3km the river is going you get the answer. 42+3= 45

Wasn't too sure what to do with the river

 

[Drongoski]

Is the answer: 43 3/4 mins?

Edit: David has posted it ahead of me.

 

[fatima96]

If you add the 3km the river is going you get the answer. 42+3= 45

Wasn't too sure what to do with the river

Thankyou for trying, it's much appreciated though

 

[fatima96]

Is the answer: 43 3/4 mins?

Yes

 

[powlmao]

Thankyou for trying, it's much appreciated though

haha thats okay. Wanted a break from economics essay writing :3

 

[fatima96]

Distance= Speed x Time

Speed = Distance/Time


Upstream : Going against the current, so subtract the river flow

(v -3) = 35km / [5/6 hrs]
v = 45km/hr

Downstream: Going with the current, so add river flow

45+3 = 35km/ [ t hours]

solve for t

t = 35 / [48] = 0.729..hours = 0.729 x 60mins = 43 minutes and 45 seconds.

Thankyou, your answer is perfect

 

[Drongoski]

As Salaam Mu'alaikum

Question is not one on Basic Arithmetic, Fatima.

 

[Demento1]

Thankyou, your answer is perfect

He should put it in LaTeX like below so the answer and working out is neater and easier to read.

Upstream : Going against the current, so subtract the river flow





Downstream: Going with the current, so add river flow



Solve for t

 

[fatima96]

As Salaam Mu'alaikum

Question is not one on Basic Arithmetic, Fatima.

Walaikum ulsalam
it is, it;s in chapter one of the understanding YEAR 11 2 & 3 UNIT mathematics text book..