Cambridge International Mathematics

246 Mensuration (solids and containers) (Chapter 11)

3 An evaporative air conditioner runs on water. It needs 12 litres to run effectively. How many 80 cl

jugs of water are needed to run the air conditioner?

4 In one city the average driver uses 30 litres of petrol per week. If there are700 000drivers in the city,

calculate the total petrol consumption of the city’s drivers in a 52 week year. Give your answer in kl.

CONNECTING VOLUME AND CAPACITY

1 millilitre (ml)of fluid fills a container of size 1 cm^3.

We say: 1 ml ́ 1 cm^3 , 1 litre ́ 1000 cm^3 and 1 kl= 1000litres ́ 1 m^3.

Example 12 Self Tutor

How many kl of water would a 3 mby 2 : 4 mby 1 : 8 m tank hold when full?

V=

=(3£ 2 :4)£ 1 : 8 m^3

=12: 96 m^3

) capacity is 12 : 96 kl.

Example 13 Self Tutor

Water pours into a cylindrical tank of diameter 4 m at a constant rate of 1 kl per hour. By how much

does the water level rise in 5 hours (to the nearest mm)?

In 5 hours the capacity of water that flows in

=1kl per hour£ 5 hours

=5kl

Since 1 kl ́ 1 m^3 , the volume of water that flows in is 5 m^3 :

Ifhmetres is the height increase, then the volume of water that must have

entered the tank is:

V=¼r^2 h

) V=¼£ 22 £h

) V=4¼h

) 4 ¼h=5 fequating volumesg

) h=

5

4 ¼

¼ 0 : 398 fdividing both sides by 4 ¼g

) the water level rises 0 : 398 m.

́ reads

‘is equivalent to’.

3m

2.4 m

1.8 m

4m

hm

area of cross-section£height

IGCSE01

cyan magenta yellow black

(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_11\246IGCSE01_11.CDR Wednesday, 29 October 2008 9:26:46 AM PETER