Question 87854
\/20 ^5 - 1 ^ \/5 = (2\/5 )^5 - 1
                  = 32 ( 5)^5/2 - 1
                  = 32 (5^5)^1/2 -1
                  = 32 (5^4 x 5)^1/2 - 1
                  = 32 x 25 x \/5 - 1
                  = 1759 approx.