( 11/16 + 7/96 - 3/40 ) : 21/240
( 11/16 + 7/96 - 3/40 ) = ( 330 + 35 - 36 )/480 = 329/480
329/480 : 21/240 = 329/480 × 240/21 = 47/2 × 1/3
= ( 47 × 1 )/( 2 × 3 ) = 47/6
