If 1/2 of the air in a tank is removed with each stroke of a vacuum pump,what fraction of the original amount of air has been removed after 4 strokes?

Description (বিবরণ) :

প্রশ্ন: If 1/2 of the air in a tank is removed with each stroke of a vacuum pump,what fraction of the original amount of air has been removed after 4 strokes?

ব্যাখ্যা:

প্রথমে stroke  =  $\frac{1}{2}$ ; দ্বিতীয়  =  $\frac{1}{4}$ ; তৃতীয়  =  $\frac{1}{8}$, চতুর্থ  =  $\frac{1}{16}$
প্রতিবার এর পূর্বের অংশ হিসেব করে  =  $\frac{8}{16}+\frac{4}{16}+\frac{2}{16}+\frac{1}{16}=\frac{15}{16}$