The number of adult tickets sold is 80.
Let's assume that the number of adult tickets sold is x, and the number of student tickets sold is y.
The drama class sold 30 more adult tickets than student tickets to the fall play. therefore,
[tex]x-y=30[/tex]
solving the equation for y,
[tex]x-y=30\\-y=30-x\\y=x-30[/tex]
Total earning through adult tickets
= Price of adult tickets x Number of adult tickets sold
[tex]= \$8 \times x\\=8x[/tex]
Total earning through student tickets
= Price of student tickets + Number of student tickets sold
[tex]= \$4 \times y\\=4y[/tex]
Total earning from all the tickets
= Total earning through adult tickets +Total earning through student tickets
[tex]840= 8x+4y\\[/tex]
Substituting the value of y,
[tex]840= 8x+4(x-30)\\840 = 8x +4x-120\\840+120=8x+4x\\960=12x\\12x=960\\\\x=\dfrac{960}{12}\\\\x= 80[/tex]
Hence, the number of adult tickets sold is 80.
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