In this question , it is given that p represents cost of 1 container of popcorn . Therefore cost of 5 containers of popcorn = 5p and cost of 3 containers of popcorn = 3p .
And g represents cost of 1 container of granola bars. THerefore cost of 4 containers of granola bars = 4g and cost of 6 containers of granola bars = 6g .
According to the given question, the required linear equations are
5p+4g=42.50 , 3p+6g =34.50 .
And these are the the required system of linear equation .