伯爵先生 2008-1-1 11:43 AM
Form 5 Maths... [1月2號交]
我想問 ge 係... 下面 lee d 數要點列式... THX
1.The value of a car is $80000. The depreciation rate of the car is 20% per year. Find the value of the car after 3 years. [$40690]
2.Solve 4 + x < 7 + x < 5x - 8. [x >3.75]
3.In a small pack of chocolate beans, there are altogether 20 red chocolate beans and green chocolate beans. After eating 2 red and 3 green chocolate beans from the pack, the ratio of the numbers of red chocolate beans and green chocolate beans is 2: 1. Find the number of red chocolate beans and green chocolate beans the pack originally has. [12 red, 8 green ]
4.F(x) = x2(x + a) +b is divisible by x – 1. When F(x) is divided by x +2, the remainder is 3, find the values of a and b. [ 4, -5]
5.(a)A factory manufactures a certain brand of rice cooker. The cost C of a rice cooker is composed into two parts, A and B. A is a constant and B varies inversely as x (in thousand), the number of the rice cookers produced. When 100 000 of rice cookers are produced, the cost of a rice cooker is 45 dollars and when 150 000 of rice cookers are produced the cost of a rice cooker is 40 dollars. Find the relation between C and x. [ c=30+1500/x]
(b)The marked price of one rice cooker is 100 dollars. During a “Big Sales” the rice cookers are sold at 50% discount. What is the percentage of profit of one rice cooker sold if the factory has produced 200 000 of the rice cookers? [33/1/3%]
6.A box contains 4 blue socks, 5 white socks and 7 red socks. Catherine draws three socks at random from the box in succession without replacement. Find the probability that
(a)no red socks are drawn, [3/20]
(b)the three socks drawn are of the same colour. [(294/(16x15x14))]
7.Solve 9^x - 3^(x+2) + 18 = 0 [ x = 1 or x = 1.63]
8.The incomes of A and B are in the ration of 3 to 2, and their expenditures are in ratio of 5 to 3. Each saves $500 a month, find their monthly income. [$3000]
9.A new car is worth $25000. Its value will depreciate to $15000 in 5 years time. Assume that the rate of depreciation per annual is a constant, find its value in 10 years time. [$9000]