notice, the denominator for each fraction is the same, thus the LCD is just 3.

Total sales = $3600
Commission earned on $3600 = $576
Commission rate can be calculated as = 
= 16%
Hence, commission rate is 16%
Hello,
Let's w the width , l the length, p the perimeter.
w=l-5
p=2(l+w)=2(l+l-5)=4l-10
4l-10=122
==>4l=122+10
==>4l=132
==>l=132/4
==>l=33
So w=33-5=28
Proof:
2*(33+28)=2*61=122