In a certain examination paper, there are n questions. For j = 1, 2 …n, there are 2n-j students who answered j or more questions wrongly. If the total number of wrong answe rs is 4095, then the value of n is

12

11

10

9

Correct Answer : A

If 7^{(x - y)} = 343 and 7^{(x + y)} = 16807, what is the value of x

[(1024)^{n/5}×4^{(2n+1)}]/[16^{n}×4^{(n−1)}]=

(5)^{1.25} × (12)^{0.25} × (60)^{0.75} =