3/8 : 9/4 + 3/8 : 9/5
= 3/8 x 4/9 + 3/8 x 5/9
= 3/8 x (4/9 + 5/9)
= 3/8 x 1
= 3/8
\(\dfrac{3}{8}:\dfrac{9}{4}+\dfrac{3}{8}:\dfrac{9}{5}=\dfrac{3}{8}\times\dfrac{4}{9}+\dfrac{3}{8}\times\dfrac{5}{9}=\dfrac{3}{8}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{3}{8}\times\dfrac{9}{9}=\dfrac{3}{8}\times1=\dfrac{3}{8}\)
3/8 : 9/4 + 3/8 : 9/5
= 3/8 : ( 9/4 + 9/5 )
= 3/8 : ( 45/20 + 36/20 )
= 3/8 : 81/20
= 3/8 x 20/81
= 60/648
= 5/54