Question 154505
Let:
{{{x}}}=no.of $2.00
{{{y}}}=no.of $5.00
So, {{{x+y=600tickets}}} ---------------------------------> eqn 1
In eqn 1 we get, {{{x=600-y}}} ---------------------------> eqn 2
Also, no.of tickets of $2.00 + no.of tickets of $5.00=$1500. To show in eqn,
{{{2.00(x)+5.00(y)=1500}}} --------------------------------> eqn 3
Substitute eqn 2 in eqn 3:
{{{2(600-y)+5y=1500}}}
{{{1200-2y+5y=1500}}}
{{{3y=1500-1200}}} -----> {{{3y=300}}} 
{{{cross(3)y/cross(3)=cross(300)100/cross(3)}}}
{{{y=100}}} ---------------------------> total of $5.00 tickets
For $2.00 tickets, go back eqn 2:
{{{x=600-100=500}}} -------------------> total of $2.00 tickets
In doubt? Go back eqn 3:
{{{2(500)+5(100)=1500}}}
{{{1000+500=1500}}}
{{{1500=1500}}}
Thank you,
Jojo