F.1數學問題(英文應用題)15點

1.) Ann has 60 stamps and May has 32.How many stamps should Ann give to Mary so that they have the same number of stamps?
Let the number of stamps to be given be x.
Afterwards, the number of stamps that Ann and May have are respectively 60 - x and 32 + x
60 - x = 32 + x
28 = 2x
x = 14
Ann should give Mary 14 stamps
2.) In a test, Peter gets 2 marks for each correct sum and loses 1 mark for each wrong sum. He does 18 sums and obtains 24 marks.How many correct sums does he get?
Let the number of correct sum be x
Then the number of wrong sum is 18 - x
His total marks is 2x - (18 - x) = 24
3x - 18 = 24
3x = 42
x = 14
He gets 14 correct sums
3.) A boy divides 60 marbles into two groups so that 7 times the smaller group is equal to 3 times the larger group.What is the number of marbles in the larger group?
Let the number of marbles in the larger group be x
Then the number of marbles in the smaller group is 60 - x
7(60 - x) = 3x
420 - 7x = 3x
10x = 420
x = 42
The larger group has 42 marbles
4.) If 5 is taken from a number and the result is then multiplied by 9 , the product is 99 . Find the number.
Let the number be x
(x - 5) * 9 = 99
x - 5 = 11
x = 16
The number is 16

1.)60-(60+32)=14

2.)24/2=12

3.)60/2=7a=3b(??)

4.)99/9-5=6

1.) Ann has 60 stamps and May has 32.How many stamps should Ann give to Mary so that they have the same number of stamps?

Ann=60
May=32

(60 + 32)/2
=92/2
=46 Ann should give 46 stamps to May.

2.) In a test, Peter gets 2 marks for each correct sum and loses 1 mark for each wrong sum.He dose 18 sums and obtains 24 marks.How many correct sums does he get?

2 -correct 18-x(number of correct)
-1- wrong x(number of wrong)

2(18-x)+ [-1(x)]=24
36-2x-x=24
-3x=-12
x=4(wrong)

18-x=18-4=14(correct)

3.) A boy divides 60 marbles into two groups so that 7 times the smaller group is equal to 3 times the larger group.What is the number of marbles in the larger group?

Let: smaller group=x larger group=60-x

x=3(60-x)
x=180-3x
4x=180
x=45(smaller group)

60-x=60-45= 15marbles(larger group)

4.) If 5 is taken from a number and the result is then multiplied by 9 , the product is 99 . Find the number.

Let the number=x
(x-5)9=99
x-5=11
x=16
The number is 16.

2009-10-16 22:16:57 補充：
3)
7x=3(60-x)
7x=180-3x
10x=180
x=18
60-x
=42(larger group)

1.)14
2.)14
3.)145
4.)3