maths again (1 Viewer)

[super.muppy]

a certain tank can b filled by 2 pipes in 80 mins. The larger pipe itself can fill the tank in 2 hrs less than the smaller pipe by itself . How long does each pipe take to fill the tank on its own.

Two trains each make a journey of 330 km. One of the trains travel 5 km/h faster than the other and takes 30 mins less time. find the speeds of each train.


plz provide some working out or a scanned copy of ur work plz
TYTYTYTYTY in advance

lols last one for 2day srsly

as u can c im pretty dum at maths lols im getting better i finks (i rage at a hard question ):burn::burn:

 

[super.muppy]

 

[Air Jordan]

Those are some weird questions... I don't how your meant to do it, and I didn't actually have a proper way (I think I guessed some random values) but if the tank can fill 20L and the big pipe goes at a rate of 10L/hr and the small pipe goes at a rate of 5L/h, then the big pipe can fill it in 120 minutes whilst the small one at 240 minutes ('larger one takes 2hrs less'). If you have them going together, then it goes at 15L/h and 15L/h for a 20L tank takes 80 minutes...
Therefore the big one takes 120minutes on its own and the small one takes 240 minutes on its own.

 

[lyounamu]

Those are some weird questions... I don't how your meant to do it, and I didn't actually have a proper way (I think I guessed some random values) but if the tank can fill 20L and the big pipe goes at a rate of 10L/hr and the small pipe goes at a rate of 5L/h, then the big pipe can fill it in 120 minutes whilst the small one at 240 minutes ('larger one takes 2hrs less'). If you have them going together, then it goes at 15L/h and 15L/h for a 20L tank takes 80 minutes...
Therefore the big one takes 120minutes on its own and the small one takes 240 minutes on its own.

Pretty nice way to set up the question. Here is mine:

[FONT=바탕]2 pipes = 1/80 of the tank per minute [/FONT]
[FONT=바탕]1st pipe = 1/x per minutes = x minutes is required [/FONT]
[FONT=바탕]2nd pipe = 1/(x+120) of the tank per minute = x+120 is required [/FONT]
[FONT=바탕] [/FONT]
[FONT=바탕](2x+120)/(x+120)x = 1/80 [/FONT]
[FONT=바탕]160x + 9600 = x^2 + 120x [/FONT]
[FONT=바탕]X^2 – 40x – 9600 = 0[/FONT]
[FONT=바탕]X = 120 and other value of x is discarded because it is negative [/FONT]
[FONT=바탕]So the first one is 120 minutes and the other one is 240 minutes which are equal to yours. [/FONT]

Another one:

x = speed
t = time

(x+5)(t -0.5)= 330
Xt = 330

Xt + 5t – 0.5x -2.5= 330
Xt = 330 ...(1)

using simultaneous eq:
5t – 0.5x -2.5 = 0
10t = 5 + x

but x = 330/t (from (1))
10t = 5 + 330/t
10t^2 - 5t - 330 = 0
t = 6, the other value is discarded
x = 55

 

[duckcowhybrid]

Thank you Lyou for typing what many of us couldn't be bothered typing. What level of Maths do you do super.muppy?

 

[lyounamu]

Thank you Lyou for typing what many of us couldn't be bothered typing. What level of Maths do you do super.muppy?

You are welcome.

To OP(original poster) and other future mathematicians out there: Please post the question on a maths forum. It's far much more likely to be noticed in that way. This question seems to have gone quite unnoticed from the date of its original post. And posting on the maths forum looks this prelim forum far much neater and "to-the-point".