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Module 1 Essential Mathematics

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Casual workers have holiday pay of 8% added on to their pay. ... Clothing shops can have very high markups on their garments - as much as 200 or 300 ... – PowerPoint PPT presentation

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Title: Module 1 Essential Mathematics


1
Module 1Essential Mathematics
  • Percentages
  • Decreasing and increasing by a percentage
  • Finding a percentage change
  • Working backwards
  • Multiple percentages
  • Exchange rates
  • Ratios

Learning objectives covered1.2-1.4
2
Using percentages
  • A percentage is a way of writing a fraction.
  • ½ 0.5 50
  • 30 of 34 30/100 34 10.20
  • 12.5 of 80 12.5 / 100 80
  • Decreasing by a percentage
  • A television costs 2000. Henry Norval is
    offering 25 off (for a short time only). How
    much will the TV cost?
  • 25 off 100 (100-25) 75
  • So the quick way is to multiply by 75 ( 0.75)
  • 2000 0.75 1500.
  • You do it
  • A fridge costs 1200. What will the price be with
    a discount of 15 ?
  • 15 off 100 (100-15) 85
  • 1200 0.85 1020

of means times
3
Increasing by a percentage
  • All the prices at a petrol station are increasing
    by 3. What will a price of 4.80 become?
  • A 3 increase is (100 3) 103 1.03
  • The price increases to 4.80 1.03 4.94400
  • This is sensibly given as 4.94.
  • Casual workers have holiday pay of 8 added on to
    their pay. Leos pay-rate without holiday pay is
    12.25 per hour. What is his pay-rate with
    holiday pay?
  • An 8 increase is (100 8) 108 1.08
  • The pay-rate with holiday pay is 12.25 1.08
    13.23
  • Clothing shops can have very high markups on
    their garments - as much as 200 or 300
  • A dress shop usually puts a 250 markup on their
    stock. A skirt is bought for 32. What will it
    retail for?
  • A 250 increase is (100 250) 350 3.5
  • The skirt will retail for 32 3.5 112.00

4
Finding a percentage change
  • The important thing is to make sure you put the
    right number on the bottom!
  • Sales went from 3200 in January to 3500 in
    February. State this as a percentage change.
  • Amanda saw a pair of shoes that cost 28 from the
    wholesaler. The shop was selling it for 70. What
    percentage mark-up is the shop using?

Calculator hint Use brackets around the top line
of the formula.
5
Working backwards
  • The price for a phone is 259 including GST. What
    is the price before the GST (of 12.5) is added?
  • The original price was multiplied by 1 12.5/100
    1.125 to get the price including GST.
  • To find the original price, we divide the 259 by
    1.125 230.22.
  • The price for a calculator is 89 including GST.
    What is the price before the GST is added?
  • 89/1.12579.11

1.125
Without GST
With GST
1.125
6
Multiple percentages
  • Nats pay-rate is 13 per hour, plus 8 holiday
    pay. He pays 18 income tax. What is his net
    hourly rate?
  • 13 1.08 0.82 11.51
  • Unless stated otherwise, you should multiply the
    effects, not add them.
  • Example
  • Price of 1000, a mark-up of 50, 12.5 GST
  • ? You DO NOT add the 50 and the 12.5 to get
    62.5, then add it on, giving 1620. ?
  • You DO multiply by (1 0.5) and by (10.125),
    giving 1667.50. ?
  • Example
  • Original price is 75, the markup is 120, and
    staff discount of 20 off retail. Price for staff
    member?
  • 75 2.2 0.8 132. ?
  • ? NOT markup less discount is 100, so price is
    150.

7
Exchange rates
  • Example
  • A DVD costs 13. The exchange rate is NZ1 buys
    0.35. How much will the DVD cost in NZ?
  • (Think will it be more or less? )
  • 13/0.35 37.14.
  • A book costs US15, plus 7 postage and packing.
    The exchange rate is NZ1 buys US0.71. How much
    will the book cost, including postage and
    packing, in NZ?
  • 15 1.07 / 0.71 22.61

0.35
NZ
UK
0.35
8
Ratios
  • Three friends, Ann, Ben and Carrie put,
    respectively, 300, 200 and 400, into a small
    business venture. They agree to split the profit
    in the ratio 324.
  • They get a profit of 1575. How much will Ann
    get?
  • Step 1 Add the values in the ratio together
  • 324 9
  • Step 2 Divide the amount by the sum of the
    ratios.
  • 1575/9175.
  • Step 3 Multiply by the part you are interested
    in.
  • 175 3 525.
  • Ann will get 525.
  • Exercise
  • They decide that since Ann is doing more work,
    the ratio should change to ratio 424.
  • How much profit will Ann get under the new ratio?
  • 424 10
  • 1575/10157.5
  • 157.5 4 630.
  • Ann will get 630.
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