The unit digit in the product $(2467)^{155}\times (341)^{72}$ is
1). 7
2). 3
3). 9
4). 1
2. If $3^{x+y}$=81 and $81^{x-y}$=3, then the value of x is
7. $(125)^{\frac{2}{3}}\times (625)^{-\frac{1}{4}}$=$5^{x}$ , then the value of x is
9. The approximate value of $\frac{3\sqrt{12}}{2\sqrt{28}}+\frac{2\sqrt{21}}{\sqrt{98}}$ is :
10. The number of prime factors in $6^{333}\times 7^{222}\times 8^{111}$