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# F.3 Percentage

1. Last year, there were 700 members in a golf club, of which 70% were male. This year, the members of male members and female members increase by 10% and 20% respectively.

(a) How many members are there in the golf club now?

(b) What is the percentage change in the number of member?

2. A bag contains some silver coins and gold coins which are in the ratio 2:5. If the number of silver coins is increased by 40% and that of gold coins is decreased by 16%, find

(a) the new ratio of the numbers of silver coins and gold coins in the bag,

(b) the percentage change in the total number of coins.

Solution:

(a) Let n be the original number of coins in the bag.

### 2 個解答

• 最愛解答

1(a) Number of members in the golf club now

=700*70%*(1+10%)+700*(1-70%)*(1+20%)

=539+252

=791

(b) The percentage change

=[(791-700)/700] *100%

=13%

2(a) Let n be the original number of coins in the bag.

The original number of silver coins in the bag

=[2/(2+5)]*n

=2n/7

The new number of silver coins in the bag

=(2n/7)*(1+40%)

=2n/5

The original number of gold coins in the bag

=[5/(2+5)] *n

=5n/7

The new number of gold coins in the bag

=(5n/7)*(1-16%)

=3n/5

The new ratio of the numbers of silver coins and gold coins in the bag

=2n/5:3n/5

=2:3

(b) The percentage change

=[(2n/5+3n/5)-(2n/7+5n/7)]/(2n/7+5n/7) *100%

=0%

資料來源： myself