Aperson leaves their house to go to the store. it takes 15 minutes at 12 mph to get to the store. they return home at 31 mph. what is the average rate of the speed for the entire trip?

Can someone me with my hwplz(only the circled ones)

Which statement best describes the polynomial

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test