英文數學題目...15點

你好 ~~~

以下是我的一些意見而已，如有錯誤請多多指教！

1.mother measures the total weight of five bottles of water.If the total weight is measured to be 4 kg 100 g,record the weight of a bottle of water in kg and g respectively.

Sol:

In kg: 4.1kg

In g: = 4 x 1000 + 100 (g) = 4100g

2.wilson drank 7 glasses of water yesterday.If each glass of water that wilson drank measured 375 mL,record the total amount of water that wilson drank yesterday in L and mL respectively.

Sol:

In L: 375 x 7 / 1000 = 2.625L

In mL: 2.625 x 1000 (mL) = 2625mL

3.it took may 25 minutes to complete one questionnaire.how many hours does it take her to complete 6 questionnaires?(express the answer in decimal if mecessary)

Sol:

The hours taken: 25 x 6 / 60 = 2.5 hrs

4.for integers that lie between 1 to 10(excluding 10 itself),subtract the sum of all the prime numbers from the sum of all the composite numbers,find the difference.

Sol:

The sum of the composite nos. = 4 + 6 + 8 + 9 = 27

The sum of the prime nos. = 2 + 3 + 5 + 7 = 17

The difference = 27 - 17 = 10

5.the fourth multiple of 9 is divided by the second multiple of 6.find the quotient.

Sol:

The fourth multiple of 9 = 9 x 4 = 36

The second multiple of 6 = 6 x 2 = 12

The quotient = 36 / 12 = 3

6.express each of 45 and 120 as a product of prime factors.hence,find the H.C.F. and L.C.M. of 45 and 120.

Sol:

45 = 3 x 3 x 5

120 = 2 x 2 x 2 x 3 x 5

The H.C.F. of 45 & 120: 3 x 5 = 15

The L.C.M. of 45 & 120 = 2 x 2 x 2 x 3 x 3 x 5 = 360

希望可以幫到你 ~~~~~

2010-08-01 16:51:12 補充：
7.jacky ate 35% of a watermelon.find the percentage of watermelon remaining.

Sol:

The percentage of watermelon remaining = 1 - 35% = 65%

2010-08-01 16:51:24 補充：
8.the area of a school hall has increased by 23% after re-construction.what percentage if the previous area is the new area?

Sol:

The new area of school hall = 1 + 23% = 1.23

The percentage = (1.23 - 1) / 1 x 100% = 23%

2010-08-01 16:51:34 補充：
9.y is 25/9 of x.what percentage of x is y?

Sol:

y = 9x / 25

y / x = 9 / 25

The percentage of x is y: 9 / 25 x 100% = 36%

2010-08-01 16:51:43 補充：
10.8/3 of all the butter cookies have been eaten.what percentage of the cookies is now left?

(*怎樣會是假分數的？？ 8/3，還是 3/8)

If yes,

Sol:

1 - 3/8 = 5/8 (The cokkies left)

5/8 x 100% = 62.5%

2010-08-01 16:51:59 補充：
Sor.. 是 cookies 才對..

2010-08-01 16:52:43 補充：
11.in a bakery,250 cakes and 400 bread were sold yesterday.the number of cakes sold today is decreased by 10% and that of bread is increased by 15%.find the total number of cakes and bread sold today.

Sol:

The total number sold:

250(1 - 10%) + 400(1 + 15%)

= 250 x 0.9 + 400 x 1.15

= 685

2010-08-01 16:52:53 補充：
12.francis had $150.he used 20% of the amount to buy stationery and 34% to buy a toy.he saved 50% of the remainder.how much did he save?

Sol:

The amount of money he remained:

150 - 150 x 20% - 150 x 34% = 150 - 30 - 51 = $69

He saved: $69 x 50% = $34.5

2010-08-01 16:53:16 補充：
13. Sol:

The no of Scientific fictions: 6 / 25% = 6 x 4 = 24

The books in the bookcase: 24 / 40% = 24 x 10 / 4 = 60

2010-08-01 16:53:21 補充：
14.in june,there were 323950000 passenger counts in public tranport. find the average number of passenger counts for each day in june,round off the answer correct to the nearest hundred thousand.

The average number of passenger : 323950000 / 30 = 10798333.33333..... = 10800000