7 boys (2 legs each) = 14 legs..............(1)

7 boys x 7 bags = 49 bags

1 bag has 7 Big cats
then 49 bags have= 49x7=343 cats

now total legs of big cats are= 343x4=1372 legs............(2)

now ever big cat is having 7 small cats

so 343 big cats have total small cats= 343x7=2401 small cats.

so total legs for small cats= 2401x4=9604 legs.........(3)

so grad total Legs will be (1)+(2)+(3)=14+1372+9604=10990 legs

Answer =10990