mahs (percentage)--urgent

a)
4.1(1+25%)(1+25%)
=6.4kg
b)
4.1(1+25%)(1+25%)(1+25%)-4.1
=3.9kg

2008-06-09 12:36:54 補充：
樓上個位
b)無叫你用百分點表示其增長率
只問你增加幾多~~~~

A new-born baby Johnny weighs 4.1kg and his weight increases steadily by 25% every week in the first 3 weeks after his birth.
(a) What is Johnny's weight at the end of the second week?
WEIGHT
=4.1(1+25%)^2
=4.1(1.25)^2
=6.4kg
(b) What is the increase in his weight in his first 3 weeks?
weight after his first 3 weeks
=4.1(1+25%)^3
=4.1(1.25)^3
=8.0kg
the increase=8.0-4.1=3.9kg

(a) Weight at the end of 2nd week = 4.1(1 + 25%)(1 + 25%) = 4.1(1.25)(1.25) =6.4Kgs.
(b) Weight at the end of 3rd week = 4.1(1.25)(1.25)(1.25) = 8Kgs.
Therefore, increase in weight = (8-4.1)/4.1 x 100% = 95.1%.