I think it would take about 1 hour and 17 minutes
-3x+5y=30
+3x+5y=30
5y=3x+30
divide 5 by everything
answer: y=3/5x+6
Answer: The cost of one sandwich is $4.25 and the cost of one cup of coffee is $2.25.
Step-by-step explanation:
Let x be the cost of one sandwich and y be the cost of one cup of coffee.
By considering the given situation, we have the following equations :-

Multiply 2 on both sides of equation (2) , we get

Subtract equation (1) from equation (3), we get

Put value of y in (1), we get

Hence, the cost of one sandwich is $4.25 and the cost of one cup of coffee is $2.25.