( 100/7 + 100/9 + 100/11) : (1/7 + 1/9 + 1/11)
=100( 1/7 + 1/9 + 1/11) : (1/7 + 1/9 + 1/11)
=( 1/7 + 1/9 + 1/11).(100:1)
=239/693.100
=23900/693
( 100 / 7 + 100 / 9 + 100 / 11 ) : (1 / 7 + 1 / 9 + 1 / 11 )
= 100 x (( 1 / 7 + 1 / 9 + 1 / 11 ) : ( 1 / 7 + 1 / 9 + 1 / 11 ))
=100 x 1
=100