If you have 3 unknowns you need at least 3 equations.
You have 2 equations with 3 unknowns.
Do you have any further information?
At the grocery store, Sal buys 7 cans of beans, a jar of peanut butter and 4 cartons of milk, which costs $28.55 total. Hal buys 9 cans of beans, a jar of peanut butter and 5 cartons of milk, which costs $35.30 total. If I buy a can of beans, a jar of peanut butter and a carton of milk, i will pay:
a 8.10 b 8.15 c 8.20 d 8.25 e 8.30
this is what i have done so far.
p--> peanut butter
m --> milk carton
but i dont know what to do from here, or whether i even started right.
help please ?