Given: Vincent has $5 bills and $20 bills. He has a total of 24 bills and the total amount is $210.
Required: To determine how many $5 bills Vincent has.
Explanation: Let Vincent has x no of $5 bills and y no of $20 bills. Then according to the question-
[tex]\begin{gathered} x+y=24\text{ , ...\lparen1\rparen} \\ 5x+20y=210\text{ ....\lparen2\rparen} \end{gathered}[/tex]Now solving the above system of linear equations by substitution, from equation (1) we get
[tex]y=24-x[/tex]Putting this value of y in eq (2),
[tex]\begin{gathered} 5x+20(24-x)=210 \\ 5x+480-20x=210 \\ -15x=-270 \end{gathered}[/tex]This gives the value of x as-
[tex]x=18[/tex]Final Answer: Option B is correct.
