Lets use the variable c for chicken and b for beef. This means we will be paying 3b, three dollars a pound of beef and, 5c, 5 dollars a pound for chicken. This means our equation will be 3b + 5c = 30
3x5 is 15 & 5x3 is 15. This gives us our total of 30 dollars. This means you can buy 5 pounds of beef and 3 pounds of chicken.
Equation 3b+5c=30
Solved Solution (3x5) + (5x3) = 30
beef + chicken = total amount spent
HOPE THIS HELPS ! Good Luck.