1. In a garden, There were 350 red tulips and 250 white tulips. Three months later, 16% of the red tulips withered but the white tulips were increased by 20%. Find the percentage change of the total number of tulips.
2. Mr Mok deposits a sum of money in a bank at 5.5% p.a. Find the sum of money that Mr Mok deposits if he can get $2310 as simple interest after 3 years.
[10分] Maths Questions (Percentage) 列明步驟..THX =]
2007-08-22 12:45 am
回答 (2)
2007-08-22 1:05 am
✔ 最佳答案
1. Number of red tulips after 3 months = 350 x (1-16%) = 294Number of white tulips after 3 months = 250 x (1+20%) = 300
Total number of tulips after 3 months= 594
Old number of tulips = 600
Percentage change of total number of tulips = (594-600)/600 x 100% = -1%
hence , percentage decreased by 1%.
2. Let $x be the sum of money
3*5.5% *x = 2,310
16.5%*x = 2,310
x = 14,000
That sum of money is $14,000
2007-08-22 12:58 am
1. New number of red tulips = 350 X ( 1 - 16%) = 294
New number of white tulips = 250 X ( 1 + 10%) = 275
The percentage change in the total number of tulips = (294 + 275 - 600) / 600 = - 5.17 %(ie negative 5 and 1 over 6 per cent)
2. Since I = PRT, so P = I/(RT) = 2310 / (5.5% X 3) = $14000.
( I = interest, P = principal, R = rate and T = time)
New number of white tulips = 250 X ( 1 + 10%) = 275
The percentage change in the total number of tulips = (294 + 275 - 600) / 600 = - 5.17 %(ie negative 5 and 1 over 6 per cent)
2. Since I = PRT, so P = I/(RT) = 2310 / (5.5% X 3) = $14000.
( I = interest, P = principal, R = rate and T = time)
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