1)Lewis is 32 years younger than his father . Seven years ago , his age
is 1/5 of his father's . Find the current age of Lewis' father.
2)A sum of money is just enough to buy 12 pears . If the price of each
pear is reduced by $0.5 , 3 more pears can be bought with the same a
mount of money . How much is the sum of money?
3)Mike has 4 times as many stamps as Kevin does . If Mike gives 16
stamps to Kevin , he still has 25 more stamps than Kevin does . How
many stamps does each of them have originally ?
Thank You!
Plz Help Me To slove Equations
2009-01-01 3:22 am
回答 (3)
2009-01-01 4:05 am
✔ 最佳答案
1) Let the current age of father's be x.5=(x-7)/(x-32-7)
5=(x-7)/(x-39)
5X-195=x-7
4x=188
x=47
2)Let the price of a pear be x.
12x=15(x-0.5)
12x=15x-7.5
-3x= -7.5
x=2.5
because 12x= he sum o money
therefore, 12(2.5)=30
3)
Let the no. of stamps that kevin has be z.
4z-16=z+16+25
4z-16=z+41
3z=57
z=19
therefore, the no. of stamps mike and kevin have are 19 and 76 respectively
參考: me
2009-01-04 8:42 am
1. Let x be the current age of Lewis's father.
x-7/5=(x-32)-7
x-7=5x-195
-4x=-188
x=47
2. Let $x be the sum of money.
x/15=(x/12)-0.5
4x=5x-30 (times 60 at both sides)
-x=-30
x=30
3. Let x be the no. of stamps Mike has.
x-16=(x/4+16)+25
x-16=x/4+41
x=x/4+57
3x/4=57 (minus x/4 on both sides)
x=76
Mike has 76 stamps and Kevin has 19 stamps.
x-7/5=(x-32)-7
x-7=5x-195
-4x=-188
x=47
2. Let $x be the sum of money.
x/15=(x/12)-0.5
4x=5x-30 (times 60 at both sides)
-x=-30
x=30
3. Let x be the no. of stamps Mike has.
x-16=(x/4+16)+25
x-16=x/4+41
x=x/4+57
3x/4=57 (minus x/4 on both sides)
x=76
Mike has 76 stamps and Kevin has 19 stamps.
參考: totally myself
2009-01-01 3:53 am
1) Let x be the age of lewis age
x - 7 = 0.2 ((x + 32) - 7)
x = 15
so lewis' father's age is 47
2) Let x be the price of the peer
12x = 15(x - 0.5)
x = 2.5
so the sum of the money is $30
3)Let x be the stamp Kevin has originally
x + 16 + 25 = 4x - 16
x = 19
so originally Kevin has 19 stamps and Mike has 76 stamps
x - 7 = 0.2 ((x + 32) - 7)
x = 15
so lewis' father's age is 47
2) Let x be the price of the peer
12x = 15(x - 0.5)
x = 2.5
so the sum of the money is $30
3)Let x be the stamp Kevin has originally
x + 16 + 25 = 4x - 16
x = 19
so originally Kevin has 19 stamps and Mike has 76 stamps
參考: me
收錄日期: 2021-04-23 18:13:22
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