Answer: [tex]\$60[/tex]
Step-by-step explanation:
Given
One ticket costs $20
Susan buys 4 tickets with 25% discount
Cost of 4 tickets is [tex]4\times 20=\$80[/tex]
On applying discount, it costs
[tex]\Rightarrow 80-80\times 0.25\\\Rightarrow 80(1-0.25)\\\Rightarrow 80\times 0.75=\$60[/tex]
So, total cost of tickets is [tex]\$60[/tex].