Q:

Jack is selling tickets to an event. attendees can either buy a general admission ticket or a vip ticket. the general admission tickets are $60 in the vip tickets are $90. he doesn't know how many of each type he has sold, but he knows he sold a total of 29 tickets and made $2100.

Accepted Solution

A:
x+y=29
60x+90y=2100

substitute the value of x as (29-y) in the second equation 
60(29-y) + 90y =2100
30y = 2100-1740=360
y=12 so x=17
so 17  general tickets were sold and 12 vip tickets were sold.