Question 188945
Let a=no of adult tickets sold
    s=no of student tickets sold

3a+2s=824

a=2s

Subsitutiting 2s for a, we get:

3*(2s)+2s=824

6s+2s=824

8s = 824

s=103

Since, a=2s we get

a=2*103

a=206

Then, there were 206 adult tickets and 103 student tickes sold for the concert