F.2 Percentages (20points) Q.8

1. Chris takes 3 hours 18 mins to complete a Marathon race this year. the time he needed is 12% less than that in last year.Find the time Chris needed to complete the race last year.

Sloution: Let "x" minutes be the time Chris needed to complete the race last year.

2.In a garden , there were 350 red tulips and 250 white tulips. three months later, 16% of red tulips withered but the white tulips were increased by 20%. Find the percentage change of the total number of tulips.

3. Natalie bought 30 boxes of cosmetics at $3600. she found that 5 boxes were expired . If she sold out the remaining at $180 per box, find the profit per cent of this trade.

4. Last year, the marked price and the selling price of a new digital camera were $7200 and $6120 respectively. But this year the marked price and the selling price are adjusted to $6400 and $5600 respectively. in comparing the discount per cent of these two years, which one is greater?

Solution: Discount per cent last year=
Discount per cent this year=

5.A computer game software marked at $280 is sold at 20%off.If the discount is 35% of its cost price, find the profit per cent.

6. Mr Mok deposits a sum of money in a bank at 5.5% p.a. Find the sum of money that Mr Mok deposits if he can get $2310 as simple interest after 3 years.

Solution Let "x" be the sum of money.

7. Flora borrows $36000 from a finance company at 3.75% p.a. simple interest. If she has to return a total amount of $ 45450, how long does she borrow?

8. A cat and a dog are not satisfied with their weights. If the weight of the cat is increased by 20% while that of the dog is decreased by percentage of the dong's original weight is the cat's originsl weight?