@_@||||||MaThEMaTiCs?_?"[urgent!!!!!!!!]

Let A be the number of $400 tickets sold
Let B be the number of $200 tickets sold
Let C be the number of $100 tickets sold

1.)the number of $200 tickets sold is 4times of $400 tickets:
B=4A
2.)the number of $100 tickets sold is 380 more than that of $200 tickets:
C=B+380
3.)the total income from the tickets is $86000:
400A+200B+100C=$86000

4.)substitute 1 into 2,
C=4A+380

sustitute 1 and 4 into 3,
400A+200(4A)+100(4A+380) = 86000
400A+800A+400A+38000 = 86000
1600A+38000 = 86000
1600A = 48000
A = 30.
Therefore, the number of $400 tickets sold is 30.

設$400, $200 及 $100門票 的賣出的票數 相對為 A, B 及 C
題目提供條件
1. the number of $200 tickets sold is 4times of $400 tickets.
=> B=4A
2. the number of $100 tickets sold is 380 more than that of $200 tickets.
=> B+380 = C
3. total income from the tickets is $86000
=> 400A + 200B + 100C = 86000

400A + 200B + 100C = 86000
=> 400A + 200(4A) + 100(380+4A) = 86000
=> 400A + 800A + 38000 + 400A = 86000
=> 1600A = 86000 - 38000
=> A = (48000 / 1600)
=> A = 30

所以, $400門票 的賣出的票數 為 30 張 #

Let the number of $400 tickets sold is a
the number of $200 tickets sold is b
the number of $100 tickets sold is c

Since the number of $200 tickets sold is 4times of $400 tickets
So, b=4a
Since the number of $100 tickets sold is 380 more than that of $200 tickets
So, c-b=380
c-(4a)=380
c=4a+380
Since the total income from the tickets is $86000
So, 400a+200b+100c=86000
400a+200(4a)+100(4a+380)=86000
1600a+38000=86000
a=30
So,the number of $400 tickets sold is30