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i.e. a b c d e f 4 2 5 6 3 1 Column a expresses ‘whole HUNDREDS’. b expresses ‘whole TENS.. c expresses UNITS (ONES). d. expresses 1/10ths e. expresses 1/100ths F. expresses 1/1000ths. 1% is expressed as a fraction as 1/100. Hence, from the ‘column rule’, 1% is 1 in column e i.e 0.01 Try to memorise the following table. It shows how identical values are expressed in different forms – percentages, fractions and decimals 100% º 100/100 º 1.00 10% º 10/100 º 1/10 º 0.1 1% º 1/100 º 0.01 0.1% º 0.1/100 º 1/1000 º 0.001 Example Calculate 17% of 3/4 Give the answer as a percentage. i. Express 17% as 17/100 ii. 17% as 17/100 ´ 3/4 (note that ‘of’ becomes ‘´‘ ) iii. The rule of multiplication of fractions applies. Multiply the top values (numerators), and multiply the bottom values (denominators) i.e (17´ 3 )/(100 ´ 4 ) = 51/400 iv. Approximate 51/400 to 50/400 v. Simplify 50/400 to 1/8 vi. Convert 1/8 to a percentage. The principle is that the 8 (denominator) has to be converted to 100 ( in this case by multiplying by 12.5). You treat the top figure in the same way (i.e 1 multiplied by 12.5 ) vii. You thus produce a fraction 12.5/100 (NB. you would not normally leave a fraction in this format). This indicates 12.5% as an APPROXIMATE ANSWER to the question. viii. Use the calculator to find the ACCURATE answer Answer 12.75% Now try these questions: i. What is 20% of £80 ? ii. What percentage of £8 is 20p ? iii. What is 50% of 5/8 ? Express the answer as a fraction. iv. By how much is 43% of 64 more than 35% of 64 ? Answer to the nearest whole number. v. Calculate 70% of 1.5 + 60% of 3.5 vi. How much (to the nearest pound) would three dozen bottles cost @ £5.75 each plus 17.5% V.A.T ? vii. Express 30p as a percentage of £50 viii. Calculate 50% of 0.005 ix. Express 7/12 as a percentage x. In a constituency of 120,680 voters the outcome of an election was as follows. Moderate Party 43% of valid votes cast Radical Party 22% of valid votes cast Extremist Party 9% of valid votes cast Countryside Party 8% of valid votes cast 15% did not cast a vote 3620 voting slips were spoiled NB. In answering the following questions, give the whole number, but regard 0.5 or more as 1. ( e.g 1.5 adjusted upwards to 2, 1.499 adjusted downwards to 1 ) x.a What was the number of the majority of votes of the Moderates over the Radicals? x.b What was the number of the majority of votes of the Moderates over all parties? x.c What percentage of the constituents spoiled their voting papers? Answers on page 20 SECTION 6 - RATIO Ratio is crudely explained as the proportion in which something or some things are shared. i.e. an expression of how the shares of the total compare with each other. Example 1 Ann, Betty and Chris win a total of £1200 in a lottery. The money is shared according to how much each staked in the lottery. Ann is to receive 2 times as much as Chris. Betty is to receive 3 times as much as Chris. How much should each receive? You need to begin by establishing the total number of shares. Begin by allocating 1 share to Chris Ann will then have 2 shares (2 times Chris’s share) Betty will receive 3 shares (3 times Chris’s share) Thus the total prize is to be shared 6 ways (1+2+3) So one share will be £1200 divided by 6 i.e £200 Chris will receive £200, Ann £400 (2 times Chris’s share), and Betty £600 (3 times Chris’s share) SECTION 6 - RATIO Ratio is crudely explained as the proportion in which something or some things are shared. i.e. an expression of how the shares of the total compare with each other. Example 1 Ann, Betty and Chris win a total of £1200 in a lottery. The money is shared according to how much each staked in the lottery. Ann is to receive 2 times as much as Chris. Betty is to receive 3 times as much as Chris. How much should each receive? You need to begin by establishing the total number of shares. Begin by allocating 1 share to Chris Ann will then have 2 shares (2 times Chris’s share) （责任编辑：职场达人） |
