急！數學中一功課！２０分（要式同答案）

1.
Let the bigger number be x
the smaller number be x-10 (Since their difference is 10)
The sum of the smaller number multiplied by 4 = 4(x-10)
Larger number multiplied by 1/3 = (1/3)x
Their sum = 25
So
4(x-10) + (1/3)x = 25
12(x-10) + x = 75
12x - 120 + x = 75
13x = 195
x = 15
Smaller number = 5

Check:
5*4 = 20
15*1/3 = 5
Their sum = 25 correct

2.
Let s be the age of Sophia
sophia is 28 years younger then dick
So Dick's age = 28+s
Gary is 1/4 of Sophia
So Gary = (1/4)s
Maria is 18 years older than Gary
So Maria = (1/4)s + 18
If maria is 28
(1/4)s + 18 = 28
(1/4)s = 10
s = 40
Sophia is 40 years old
Dick is 28+40 = 68 years old.

Check.
Dick = 68
Sophia = 40
Gary = 10
Maria = 10+18 = 28 correct

1.Let the smaller number be x, the larger no be y
y-x=10
y=10+x
4x+y/3=25
12x+y=75
12x+10+x=75
13x=65
x=5
y-5=10
y=15


2.Let age of Dick be y,
(y-28)x(1/4)+18=28
(y-28)x(1/4)=28-18
(y-28)x(1/4)=10
y-28=40
y=68

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1.
let the larger number be b and the smaller number be a
b-a=10
b=10+a----------(1)

4a+1/3b=25---(2)

sub(1)to(2),
4a+1/3(10+a)=25
4a+10/3+1/3a=25
13/3a=25-10/3
a=5----------------(3)

sub(3)to(1)
b=10+5
b=15

Therefore,a=5 and b=15

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2.
let the age of Sophia be a ,Dick be b , Gary be c ,and Maria be d
a+28=b-----(1)

1/4a=c------(2)

d=28----------(3)

d-18=c-------(4)

sub(3)to(4)
c=10

sub c=10 to(2)
a=40

sub a=40 to(1)
b=68

Dick was 68 years old.

1. let larger number=x, smaller number=y;

x-y=10, so y=x-10 (1)
4y+(x/3)=25 (2),
(1) into (2),
4*(x-10)+(x/3)=25
4x-40+(x/3)=25
4x+(x/3)=25+40
(12x/3)+(x/3)=65
13x/3=65
x=15,
therefor x=15 and y=x-10=15-10=5

你個答案一定錯,5同10之間相差只有5,點會有"The difference between two numbers is 10."出現!!!!

2.Because Maria is 28 years old,so
Gary is 28-18=10 years old
then Sophia is 4*10=40 years old
finally Dick is 40+28=68 years old

1.let the smaller number be x,
4x+(1/3)(x+10)=25
12x+1(x+10)=75
13x=75-10
x=65/13
x=5
the greater number=x+10
=5+10
=15

2.Let age of Dick be y,
(y-28)x(1/4)+18=28
(y-28)x(1/4)=28-18
(y-28)x(1/4)=10
y-28=40
y=68

1.
Let the smaller number be x, the larger no be y
y-x=10
y=10+x
4x+y/3=25
12x+y=75
12x+10+x=75
13x=65
x=5
y-5=10
y=15?

2.
68