Answer :

9.

( 5 / 8 ) * ( 2 / 3 ) = 10 / 24 = 5 / 12  A ;

10.

( 11 / 12 ) ÷ ( 5 / 7 ) = ( 11 / 12 ) * ( 7 / 5 ) = 77 / 60 = 1 17 / 60 D ;
 
11.

3 / 8  B;

12.

2 5 / 8 = 21 / 8 ; the reciprocical of 21 / 8 is 8 / 21 C ;

13.

$12.50 * 34.5 =$ 431.25  C ;