154 Formulae and simultaneous equations (Chapter 7)Example 7 Self Tutor
Write a formula for the amount$Ain a person’s bank account if initially the balance was:
a $5000, and$200was withdrawn each week for 10 weeks
b $5000, and$200was withdrawn each week forwweeks
c $5000, and$xwas withdrawn each week forwweeks
d $B, and$xwas withdrawn each week forwweeks.a A= 5000¡ 200 £ 10 b A= 5000¡ 200 £w
) A= 5000¡ 200 w
c A= 5000¡x£w
) A= 5000¡xwd A=B¡x£w
) A=B¡xwEXERCISE 7C
1 Write a formula for the amountEAin a new savings account given monthly deposits of:
a E 200 over 17 months b E 200 overmmonths c EDovermmonths2 Write a formula for the amount$Ain a bank account if the initial balance was:
a $2000, and then$150was deposited each week for 8 weeks
b $2000, and then$150was deposited each week forwweeks
c $2000, and then$dwas deposited each week forwweeks
d $P, and then$dwas deposited each week forwweeks.3 Write a formula for the total cost$Cof hiring a plumber given a fixed call out fee of:
a $ 40 plus$ 60 per hour for 5 hours of work
b $ 40 plus$ 60 per hour forthours of work
c $ 40 plus$xper hour forthours of work
d $Fplus$xper hour forthours of work.4 Write a formula for the amountEAin Leon’s wallet if initially he had:
a E 200 , and he bought 8 presents costingE 5 each
b E 200 , and he boughtxpresents costingE 5 each
c E 200 , and he boughtxpresents costingEbeach
d EP, and he boughtxpresents costingEbeach.5 Write a formula for the capacity,Clitres, of a tank if initially the tank held:
a 5000 litres, and 10 litres per minute for 200 minutes ran out through a tap
b 5000 litres, andrlitres per minute for 200 minutes ran out through a tap
c 5000 litres, andrlitres per minute formminutes ran out through a tap
d Llitres, andrlitres per minute formminutes ran out through a tap.IGCSE01
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Y:\HAESE\IGCSE01\IG01_07\154IGCSE01_07.CDR Monday, 15 September 2008 4:11:00 PM PETER