Equation :
1 . Garrett is now three times as old as Rico . 5 years ago , Garrett was four times as old as Rico . How old is Garrett now .
2 . The total number of tickets sold for a school play was 450 and the money received for the tickets sold was $2600 . If adult ' s tickets were sold at $ 7.5 each and student ' s tickets were sold at $5 each , how many tickets of each kind were sold ?
6 . Solve the following literal equations for X .
(a) . a + b ( X + 1 ) = c
(b) . y = 1/4X - 2
中一數學 ( 超急 )
2008-11-27 2:56 am
回答 (2)
2008-11-27 6:42 am
✔ 最佳答案
1.Let A be the age of GarrettLet B be the age of Rico
A=3B--------------------(1)
A-5=4(B-5)-------------(2)
A-5=4B-20
A=4B-15------------- (3)
Sub (3) into (1):
4B-15=3B
B=15---------------(4)
The age of Rico is 15 years old.
Sub (4) into (1):
A=45
The age of Garrett is 45 years old now.
2.Let A be the number of tickets bought by adults
Let B be the number of tickets bought by students
A+B=450------------------------(1)
7.5A+5B=2600------------------(2)
(1)*5:
5A+5B=2250---------------------(3)
(3)-(2):
-2.5A=-350
A=140-----------------------(4)
The tickets of adults were sold were 140.
Sub (4) into (1):
140+B=450
B=310
The tickets of students were sold were 310.
6.(a)a + b ( X + 1 ) = c
b ( X + 1 ) = c-a
X+1=(c-a)/b
X=(c-a)/b-1
(b)y = 1/4X - 2
y+2=1/4X
X=4y+8
2008-11-27 3:47 am
1. Let G be the age of Garrett. R be the age of Rico
G=3*R; or R=G/3
(G-5)=4*(R-5) or R = (G-5)/4+5
Therefore, G/3 = (G-5)/4+5
G= 3*(G-5)/4 + 15
4G=3*(G-5)+60=3G+45
G=45
There Garrett is 45 years old now
2. Let A be the number of adult ticket sold. S be the number of student ticket sold.
A+S = 450; or 5 * A + 5 * S = 2250
7.5 * A + 5 * S = 2600
Therefore, 2.5 * A = 350
A = 140
S = 310
6(a)
a + b(X + 1) = c
b(X + 1) = c-a
X+1 = (c-a) / b
X = (c-a)/b -1
(b)
y = 1/4X -2
y+2 = 1/4 X
X=4y+8
G=3*R; or R=G/3
(G-5)=4*(R-5) or R = (G-5)/4+5
Therefore, G/3 = (G-5)/4+5
G= 3*(G-5)/4 + 15
4G=3*(G-5)+60=3G+45
G=45
There Garrett is 45 years old now
2. Let A be the number of adult ticket sold. S be the number of student ticket sold.
A+S = 450; or 5 * A + 5 * S = 2250
7.5 * A + 5 * S = 2600
Therefore, 2.5 * A = 350
A = 140
S = 310
6(a)
a + b(X + 1) = c
b(X + 1) = c-a
X+1 = (c-a) / b
X = (c-a)/b -1
(b)
y = 1/4X -2
y+2 = 1/4 X
X=4y+8
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