Question 156488
s+2c=100
s=100-2c
50s+75c=4,000
50(100-2c)+75c=4,000
5,000-100c+75c=4,000
-25c=4,000-5,000
-25c-1,000
c=-1,000/-25
c=40 number of couple tickets.
100-2*40=100-80=20 single tickets.
Proof:
50*20+75*40=4,000
1000+3,000=4,000
4,000=4,000