Summer used 2/5 of her ground beef to make burgers if she used 3/4 pound of beef how much did he have at first

You need to divide 2/5 and 3/4. First, you need to do "Keep Change Flip". We do this by keeping 2/5 the same, changing the division sign to a multiplication sign and flipping 3/4 to make 4/3. Lastly, you add them up and get your answer.

2/5 : 3/4

2/5 X 4/3 = 8/15