Expert please solve the 1st question :

Solution 
Let Breadth = B
Given:
Length = L = 3$\frac{1}{2}B=\frac{7}{2}B$
So,
Perimeter of the rectangular field = 2(L + B)
99(given) = $2\left(\frac{7}{2}B+B\right)=2\left(\frac{9}{2}B\right)=9B$          
99 = 9B
or
9B = 99
B = $\frac{99}{9}=11m$
Now,
L = $\frac{7}{2}B=\frac{7}{2}\times 11=\frac{77}{2}=38.5m$