Question 102216
Suppose that the number of tickets sold for general admission is x and the numbers of tickets sold for students is y. If we try to put the problems into equations,
{{{ x + y = 240 }}} ... (1)
{{{ 8x + 5y = 1680 }}} ... (2)

Therefore you can work out the solution algebraically, such as by substitution:
x = 240 - y from equation (1), and submitting this value of x into (2) makes:
{{{ 8*(240 - y) + 5y = 1680 }}}
{{{ 1920 - 8y + 5y = 1680 }}}
{{{ -8y + 5y = 1680 - 1920 }}}
{{{ -3y = -240 }}}
{{{ y = 80 }}}

To find x, we can use (1) and submit this value of y
{{{ x + 80 = 240 }}}
{{{ x = 240 - 80 }}}
{{{ x = 160 }}}

Therefore, 160 tickets were sold for general admission and 80 for students.

Hope that helps :)