Kayla and her children went into a restaurant and she bought $63 worth of hotdogs
and tacos. Each hotdog costs $3.50 and each taco costs $4. She bought 3 more
hotdogs than tacos. Write a system of equations that could be used to determine the
number of hotdogs and the number of tacos that Kayla bought. Define the variables
that you use to write the system.