If 10^2y = 25, then 10^-y equals

(a) $-\frac{1}{5}$

(b) $\frac{1}{50}$

(c) $\frac{1}{625}$

(d) $\frac{1}{5}$

If 10^2y=25 then 10^-y equals?

If ${10}^{2y}=25,then{10}^{-y}$ equals

$-1[a-3\{b-4(a-\overline{b-8})+4a\}+10]$ equals

If $a_1,a_2,\cdot \cdot \cdot ,a_{15}$ are in A.P. and $a_1+a_8+a_{15}=15$, then $a_2+a_3+a_8+a_{13}+a_{14}$ equals