10 cm8cm210 Topics in arithmetic (Chapter 10)EXERCISE 10A
1 Write as a percentage:
a 107 b^1350 c 253 d 20011 e 2
f 0 : 2 g 0 : 05 h 1 i 0 : 98 j 0 : 003
2 Write as a fraction in simplest form and also as a decimal:
a 75% b 7% c 1 :5% d 160% e 113%3 Express as a percentage:
a 35 marks out of 50 marks b 3 km out of 20 km
c 8 months out of 2 years d 40 min out of 2 : 5 hours4 Tomas reduces his weight from 85 : 4 kg to 78 : 7 kg. What was his percentage weight loss?5 If17%of Helen’s assets amount toE43 197, find:
a 1%of her assets b the total value of all her assets.6 Find:
a 20%of 3 kg b 4 :2%of$26 000 c 105%of 80 kg
d 114 %of 2000 litres e 0 :7%of 2670 tonnes f 46 :7%of$35 267: 207 Alex scored72%for an examination out of 150 marks. How many marks did Alex score?8aA marathon runner starts a race with a mass of 72 : 0 kg.
Despite continual rehydration he loses3%of this mass
during the race. Calculate his mass at the end of the race.
b Another runner had a starting mass of 68 : 3 kg and a
finishing mass of 66 : 9 kg. Calculate her percentage loss
in mass.9 Petra has a monthly income of$ 4700. She does not have to pay any tax on the first$ 2400 she earns,
but she has to pay15%of the remainder as tax.
a How much tax does Petra have to pay?
b How much does Petra have left after tax?
c What percentage of the$ 4700 does Petra actually pay in tax?10 If 3 students in a class of 24 are absent, what percentage are present?11 After 2 hours a walker completed 8 km of a journey of 11 : 5 km. Calculate the percentage of the journey
which remains.12 The side lengths of the rectangle are increased by20%. What
is the percentage increase in the area of the rectangle?13 A circle’s radius is increased by10%. By what percentage does its area increase?IGCSE01
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Y:\HAESE\IGCSE01\IG01_10\210IGCSE01_10.CDR Thursday, 2 October 2008 12:05:22 PM PETER