Question

625 students enter a 100 m race. the track has five lanes. at the end of each race the winner survives, while the other four are eliminated. how many races are needed to determine the champion??

Answer 1

total number of student remaining after completing one time equal to
=625/5
=125

Again and after completing remaining students
=125/5
=25
again after completing
=25/5
=5
and last time completing
=1
total number of race
=125+25+5+1
=156