1.In a party,the number of adults is 7 more than 9 times that of children. The total number of people there is 67. Set up an equation for finding the number of children.
2. After 16 years, Kenneth will be 2 times as old as he was 12 years ago. Set up an equation for finding his current age.
3. For two consecutive even numbers, 3 times of the larger number is 22 more than 2 times the smaller number. Find the two numbers.
4. The total weight of 130 packs of sugar is 134 kg. Some of them weigh 0.5 kg and the others weigh 2 kg each. How many packs of sugar weighs 0.5 kg each?
5. A sum of money is just enough to buy 35 vases. If the price of each vase increases by $120, 10 less vases can be bought with the same amount of money. Find the original price of each vase
F1 maths題(Equation)[急]
2009-12-10 1:02 am
回答 (2)
2009-12-10 1:12 am
✔ 最佳答案
(1) Let the number of children be xThe number of adults = 9x + 7
Total number of people = x + 9x + 7 = 67
10x = 60
x = 6
There are 6 children
(2) Let his current age be x
(16 + x) = 2(x - 12)
16 + x = 2x - 24
x = 40
His current age is 40
(3) Let the smaller number be x
Then the larger number is x + 2
3(x + 2) = 22 + 2x
3x + 6 = 22 + 2x
x = 16
The 2 numbers are x and x + 2 or 16 and 18
(4) Let the number of bags of sugar that weighs 0.5 kg be x
Then the number of bags of sugar that weighs 2 kg = 130 - x
0.5x + 2(130 - x) = 134
0.5x + 260 - 2x = 134
126 = 1.5x
x = 84
The number of bags of sugar that weighs 0.5 kg is 84
(5) Let the original price of each vase be $x
The original sum = $35x
After price increase, (x + 120)(35 - 10) = 35x
25(x + 120) = 35x
25x + 3000 = 35x
10x = 3000
x = 300
The original price is $300 each
2009-12-10 1:35 am
1. Let x be the number of children.
9x+7=67-x
x=6
2. Let x be his current age.
16+x=2*12
x=8
3. Let x be the smaller number, (x+2)be the bigger one.
3(x+2)=22+2x
x=16
4. Let x be the number of packs of sugar weighs 0.5 kg.
0.5x+2(130-x)=134
0.5x+260-2x=134
126-1.5X=0
x=84
5. Let x be the original price of each vase .
35x= 120*(35-10)
35x=3000
x=85.7 (corr. to 3 sig. fig.)
9x+7=67-x
x=6
2. Let x be his current age.
16+x=2*12
x=8
3. Let x be the smaller number, (x+2)be the bigger one.
3(x+2)=22+2x
x=16
4. Let x be the number of packs of sugar weighs 0.5 kg.
0.5x+2(130-x)=134
0.5x+260-2x=134
126-1.5X=0
x=84
5. Let x be the original price of each vase .
35x= 120*(35-10)
35x=3000
x=85.7 (corr. to 3 sig. fig.)
參考: 自己
收錄日期: 2021-04-23 23:19:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091209000051KK00914