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IGCSE MATHS Doubts

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ksitna:
i dont get how they did this

Factorise completely m^4n ? 16n^5.

Adzel:
same paper A@di Q4 part (f), Q5 part (b) + explaination...please  :)

Vin:

--- Quote from: Adzel on May 18, 2010, 02:56:34 pm ---O/N 2004 04 Q3 part (b) and (c) + explaination.....please  :)

--- End quote ---

this one is quite easy ..

3 a) V= pi * r2 *h
= pi * 402 *110
=552920.3
=553000 cm3

b) in this one water comes out at the speed of 14 cm/s through 1.6 cm2

so 14 * 1.6 volume of water comes out if the pipe
= 22.4 cm3/sec

meaning 22.4 cubic cms of water will pass every sec .. so how long does it take to fill the cylinder ..

so time taken would be
553000
--------
  22.4
=24687.5 sec / 60
= 411.45833333 mins /60
= 6.8576389 hrs
=6 hrs 51 mins


c) in this one the SA is given .. so ..
SA in mm = 70 * 100 * 100
= 700000 mm2

vol = SA * h
553000 = 700000 * h
h = 0.79 cm
= 7.9 mm

 ;)

$H00t!N& $t@r:
need help with p4 O/N 2005 Q7c(ii)

Vin:

--- Quote from: Shooting Star on May 18, 2010, 04:25:21 pm ---need help with p4 O/N 2005 Q7c(ii)

--- End quote ---

ok gimme 2 mins

volume of pool = 1512 m3 * 100 *100 *100
=1512000000 cm3

volume of pipe = 6870 cm3

=1512000000 cm3
-----------------
    6870 cm3

=ans / 60(min) * 60(hrs) *24

=2.5473 days
=2 days 13 hrs

sorry net prob. !!

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