Cambridge International Mathematics

Challenge #endboxedheading

168 Formulae and simultaneous equations (Chapter 7)

10 Eric and Jordan were each given$8to spend at a candy

store. Eric bought 2 chocolate bars and 5 lolly bags,

while Jordan bought 4 chocolate bars and 2 lolly bags.

Neither child had any money left over. Find the cost of

a chocolate bar.

1 Pat thinks of three numbers. Adding them in pairs he obtains answers of 11 , 17 and 22. What are

the numbers?

2 Solve forx: 373 x+ 627y= 2492

627 x+ 373y= 3508

Hint: There is no need to use the technique of ‘elimination’. Look at the two equations carefully.

3 Finda,bandcgiven that: ab=c

bc=a

ca=b

4 How many four digit numbers can be found in which

² the first digit is three times the last digit

² the second digit is the sum of the first and third digits

² the third digit is twice the first digit?

5 What can be deduced abouta,bandcif a+b=2c and b+c=2a?

6 Findx,yandzif:

a x+y¡z=10

x¡y+z=¡ 4

2 x+y+3z=5

b x+y¡z=8

2 x+y+z=9

x+3y+z=10

7 If a+b=1and a^2 +b^2 =3, find the value of ab.

IGCSE01

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Y:\HAESE\IGCSE01\IG01_07\168IGCSE01_07.CDR Monday, 27 October 2008 9:33:37 AM PETER