Только под б) пж !!!!!!!!

$11 \frac{1}{5} :7 = 10 \frac{1}{2} :x \\ \\ 11 \frac{1}{5} x = 7 * 10\frac{1}{2} \\ \\ x= \frac{7*21*5}{1*2*56} = \frac{1*21*5}{1*2*8} = \frac{105}{16} \\ \\ x=6 \frac{9}{16}$

Проверим:
$11 \frac{1}{5} :7 = 10 \frac{1}{2} :6 \frac{9}{16} \\ \\ \frac{56*1}{5*7} = \frac{21*16}{2*105} \\ \\ \frac{8*1}{5*1} = \frac{1*8}{1*5} \\ \\ 1 \frac{3}{5} = 1 \frac{3}{5}$