The mean deviation of an ungrouped data is 50. If each observation is increased by 2%, then the new mean deviation is 

If $x_1\dots x_n$ are the observations then the new
observations are $\left(1.02\right)x_1,\left(1.02\right)x_2..,\left(1.02\right)x_n$

Therefore the new mean $=\left(1.02\right)\overline{x}$

New mean deviation $=\frac{1}{n}\sum \left|\left(1.02\right)x_i-\left(1.02\right)\overline{x}\right|$

                                  $\begin{array}{l}=\left(1.02\right)\frac{1}{n}\sum \left|x_i-\overline{x}\right|\\ =\left(1.02\right)\times 50=51\end{array}$