F.4 MATHS.................................
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F.4 MATHS
2010-05-29 2:07 am
回答 (2)
2010-05-29 2:22 am
✔ 最佳答案
T = k * wn......(1)If T is doubled and n is tripled , let the % increase of w = R% , then :
2T = k * w(1 + R%) * 3n
By (1) :
2k * wn = k * w(1 + R%) * 3n
2 = 3(1 + R%)
R% = 2/3 - 1 = - 1/3 = - 0.333... = - 33.3333....%
So w decrease 33.3333.....%
2010-05-29 2:50 am
Let original time = T
original weight = w and
original number of eggs = n
so T = kwn, or w = T/kn.
New T = 2T, new number of eggs = 3n
so new weight = 2T/k(3n) = 2T/3kn.
so % change in weight
= [ 2T/3kn - T/kn]/(T/kn) x 100%
= (T/kn)(2/3 - 1)/(T/kn) x 100%
= (2/3 - 1) x 100%
= (-1/3) x 100%
= - 100/3 %.
original weight = w and
original number of eggs = n
so T = kwn, or w = T/kn.
New T = 2T, new number of eggs = 3n
so new weight = 2T/k(3n) = 2T/3kn.
so % change in weight
= [ 2T/3kn - T/kn]/(T/kn) x 100%
= (T/kn)(2/3 - 1)/(T/kn) x 100%
= (2/3 - 1) x 100%
= (-1/3) x 100%
= - 100/3 %.
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