Help MATH [複製鏈接]

 Find the new value in each of the following questions.




a)90 is increased by 5% and then increased by 6%


b)10mm is decreased by 40% and then increased 20%


c)$300 is decreased by 40% and then increased 20%


d) minutes is increaed (300/7)% and then decreased by 30 %



e)100kg is decreased by 35% and then decreased by 10%


f)65km is increased by 15% and then increased (1-90%)


d)320hours is decreased by 32% and then increased by 32%

a)90 is increased by 5% and then increased by 6%

  90X(1+5%)X(1+6%)
=90X1.05X1.06
=100.17

b)10mm is decreased by 40% and then increased 20%
  10X(1-40%)X(1+20%)
=10X0.6X1.2
=7.2mm

c)$300 is decreased by 40% and then increased 20%
  300X(1-40%)X(1+20%)
=300X0.6X1.2
=$216

d) minutes is increaed (300/7)% and then decreased by 30 %
  1X(1+300/7%)X(1-30%)
=1X(100%+300/7%)X0.7
=1X(142 6/7%)X0.7
=0.7X(1000/7%)
=(0.7 X 1000 / 7)%
=100%
=1minute      ←這一題跟本是玩人的說

e)100kg is decreased by 35% and then decreased by 10%
  100X(1-35%)X(1-10%)
=100X0.65X0.9
=58.5kg

f)65km is increased by 15% and then increased (1-90%)
  65X(1+15%)X(100%+1-90%)
=65X1.15X1.1
=82.225km

d)320hours is decreased by 32% and then increased by 32%
  320X(1-32%)X(1+32%)
=320X0.68X1.32
=287.232hours

給我300icashXDDD

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[ 此帖被瑋哥在2008-05-10 20:58重新編輯 ]

a:100.17
b:7.2
c:216
d:唔識- -
e:58.5
f:82.225
g:287.232

a.100.17
b.7.2mm
c.216
d.1min
e唔知
f.8.225km
g.287.232