Question 109139
Please help me with this word problem: Write a system of two equations in two unknowns for each problem. Solve each system by substitution. 
Tickets for a concert were sold to adults for $3 and to students for $2. 
If the total receipts were $824 
and twice as many adult tickets as student tickets were sold, 
then how many of each were sold? 
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Let # of adult tickets be "a" ; Let # of student tickets be "s".
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EQUATIONS:
Quantity: a = 2s
Value:   3a+2s = 824
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Substitute to solve for "s", as follows:
3a + 2(2s) = 824
7s = 824
s = 117.714...
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Comment: # of student tickets should turn out 
to be a whole number.  Check your problem
statement.
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Cheers,
Stan H.