Which of the following fraction sets is arranged in descending order?

Which of the following fractions has a reciprocal that is a proper fraction?

Which of the following fractions is the largest: 4/5, 7/8, 6/7, 5/6?

A number X lies between 0 and 1. Which of the following is true?

If bc + cd = 2bd and a + c = 2b, then which one of the following is correct?

If (3a +6b +c +2d) x (3a - 6b - c +2d) = (3a - 6b +c- 2d) x (3a +6b - c- 2d), then which one of the following is correct ?