There is graphical representation error, even I read incorrectly i read as 1/2^1 * 15^7 but it is 1/{(2^11) * (5^7)} .Hope it helps

Now comming back to question to make the decimal terminating we have to bring the decimal in the form $2^n * 5^n$

From the equation $\frac{1}{2^{11} * 5^7}+ \frac{1}{2^7 * 5^{11}}$

We take$\frac{1}{(2^7 * 5^7)} * [\frac{1}{(2^4)} + \frac{1}{(5^4)}]$

= $\frac{1}{10^7}$ $[\frac{1}{16}$ + $\frac{1}{625}]$
= $\frac{1}{10^7}$ $[\frac{641}{10^4}]$
= $\frac{641}{10^{11}}$
= 8 decimal point ( since 641 >100)