Maths

5.The number of members in a club increases from 40 to 60 .What is the percentage increase in the number of club members?
會員的增長率
(60 – 40) x 100%/ 40
= 50%

7.In a reading programme, the number of participants increases from 8 to 32. Find the percentage increase in participants.
參加者的增長率
(32 – 8) x 100%/ 8
= 300%

9.The for 1L of diesel decreased from $4.5 to $3.6. Fnd the percentage decrease in price.
柴油的減價率
(4.5 – 3.6) x 100%/ 4.5
= 20%

11.Find the new values after the changes.
a)120 increases by 20% then decreases by 20%
120(1+20%)(1-20%)
= 115.2

b)96 decreases by 50% then increases by 30%
96(1-50%)(1+30%)
= 62.4

5. the percentage increase :
(60-40)/40*100%
=50%

7. the percentage increase :
(32-8)/8*100%
=300%

9. the percentage decrease :
(4.5-3.6)/4.5*100%
=20%

11a) the new value :
120(1+20%)(1-20%)
=120*1.2*0.8
=115.2

11b) the new value :
96(1-50%)*(1+30%)
=96*0.5*1.3
=62.4

5. 60-40/40 X 100%
=50%
7 . 32-8 /8 X100%
=300%
9. 4.5-3.6 /4.5 X100%
=20%
11a) 120X(1+20%)X(1-20%)
=144X80%
=112
b) 96X(1-50%)X (1+30%)
=48X 130%
=62.4