Respuesta :

(311&1/4-186&3/4)/(5-3)=62&1/4
so the difference between each adjacent number is 62&1/4
when the top number is 4, the bottom number is 186&3/4+62&1/4=249 (a)
when the top number is 4, the bottom number is 311&1/4+62&1/4=373&1/2 (b)
C=10