數學題(英)

#1 the sum of three consecutive integers is 45 .what are these number?
let the three consecutive integers be x-1 , x,x+1 [it's easier to solve]
x+(x-1)+(x+1)=45
3x=45
x=15
therefore, the three consecutive integers are 14,15,16
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2.solve 7(x-1)-5(2-x)=3

7(x-1)-5(2-x)=3
7x-7-10+5x=3
12x=20
x=5/3
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3.paul gets some 20-dollar nites and 50-dollar notes.it is known that he has $360 and the number of 20 dollar notes is grearter than that of 50 dollars by 4.find the number of 20 dollar notes .
let the number of 20 dollar notes be x ,
so the number of 50 dollar notes be (x-4)
20x+(x-4)(50)=360
70x=560
x=8
so the number of 20 dollar notes is 8
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4.connie used 八分之三 of her pocket money to visit the zoo.it is known that $75 remaind.how much pocket money did she have?
assume she had $x pocket money
x-3/8x =75
5/8x=75
x=120
so she had $ 120 pocket money

1.let y be the smallest number ,
that (y+1) is the smaller number ,
(y+2)is the biggest number ,

y+ (y+1) + (y+2) =45
3y+3=45
3y=42
y=14

so the number is 14 , 15, and 16.

2.
7(x-1)-5(2-x)=3
7x-7-10+5x=3
12x-17=3
12x=20
x=1&2/3

3.
let 50y be the number of 50-dollar notes,
that 20(y+4) be the number of 20-dollar notes ,

50y+20(y+4)=360
70y+80=360
y=4

4+4=8

so there are 8 20-dollar notes.

4.
let y be the money she has ,
y(1-3/8)=75
y5/8=75
y=120

so she has $120.

the sum of three consecutive integers is 45 .what are these number?
x+(x+1)+(x+2)=45
3x+3=45
x=14
the three numbers are: 14,15,16

solve 7(x-1)-5(2-x)=3
7x-7-10+5x=3
12x=20
x=20/12= 5/3

paul gets some 20-dollar nites and 50-dollar notes.it is known that he has $360 and the number of 20 dollar notes is grearter than that of 50 dollars by 4.find the number of
20 dollar notes .

Let x be the number of $20 notes, y be the number of $50 notes

F1: 20x + 50y = 360
F2: x= y+4

Put F2 into F1:

20(y+4) + 50y = 360
70y + 80 = 360
70y = 280
y = 4
x = y +4 = 4+4 = 8

connie used 八分之三 of her pocket money to visit the zoo.it is known that $75 remaind.how much pocket money did she have?

Let x be the money Connie has

X x (1 - 3/8) = 75
5X / 8 = 75
5X = 600
X =120