$2$ reactions happening inside a reactor: C$-->$E$+$B and $3$C$-->2$D$+3$B

i input $10$ moles of C in the reactor. the product selectivity ratio is $10$:$7$ for D:E $($so for every $10$ moles of D made, $7$ moles of E will be made.$)$

what is the number of moles of C that will be consumed in each reaction? assume all of the C is converted.