Amongst the following fractions, the largest and second largest fractions, respectively are 5/6, 3/4, 1/2, 2/3, 3/5

Converting each to decimal: 5/6 ≈ 0.833, 3/4 = 0.75, 1/2 = 0.5, 2/3 ≈ 0.667, 3/5 = 0.6. Arranged in decreasing order: 5/6 > 3/4 > 2/3 > 3/5 > 1/2. Hence the largest is 5/6 and the second largest is 3/4.