Yesterday, stanley's doughnut shop sold 2/3 as many chocolate doughnuts as cinnamon doughnuts. if they sold 7 1/4 trays of cinnamon doughnuts, how many trays of chocolate doughnuts did they sell?

You figure out the amount of chocolate doughnuts sold by multiplying 2/3 by 7 1/4

first you change 7 1/4 to an improper fraction:

7 1/4 = 29/4

now multiply 2/3*29/4 by multiplying the two numerators then putting that over the two denominators multiplied: (2*29) / (3*4) = 58/12

now simplify:58/12=4 10/12 = 4 5/6

the answer is Stanley's doughnut shop sold

4 5/6 trays of chocolate doughnuts