O-LevelMathematicsNumber4024/22 · May/June 2022 · Q110 Marks

In 2021, the cost of posting a letter was 84 cents. A company posts 1950 letters. Find the cost, in dollars, to post these letters.

(a)(i)In 2021, the cost of posting a letter was 84 cents. A company posts 1950 letters. Find the cost, in dollars, to post these letters.[1]
(a)(ii)In 2022, the cost of posting a letter is 96 cents. Calculate the percentage increase in the cost of posting a letter.[2]
(b)Cost of posting a letter is 96 cents 15% discount when monthly postage is more than $1000 Company A posts 1200 letters in one month. Company B posts fewer letters than Company A in the same month. Company A and Company B each pay the same amount to post their letters that month. Find the number of letters Company B posts in that month.[3]
(c)In 2022, the cost of posting a parcel with a mass of 1 kg or less is $4.60. The cost increases by $1.10 for each additional 0.5 kg. Find the cost of posting a parcel with a mass of 3.5 kg.[2]
(d)The cost of posting parcels increases by 7.2%. After the increase, the cost of posting a parcel is $13.40. Calculate the original cost of posting this parcel.[2]

Mark scheme

Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.

[1] 1638[.00]
[2] M1 for (96-84)/84 [x100] oe or 96/84 x100 [-100]oe
[3] M2 for 1200x(1 - 15/100) oe OR M1 for (1200x96) - (15/100)x(1200x96) oe or B1 for 17280 (cents) or ($)172.8[0] M1 for their97920 / 96 oe After 0 scored, SC2 for answer 1020 from consistent use of figs96
[2] M1 for 1.10x(3.5-1)/0.5 oe
[2] M1 for 100/(100+7.2) x = 13.4[0] soi

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