Suppose
W = 4
so there are 4 weeks and 4 days
The question is how many days in total
there are 7 days in a week= so 1 week= 7
4 week+ 4 days= 28 days + 4 Days= 32 days
You give any value to W like 5,6, 7 whatever the answer will be same
8W= 8x4 = 32 days
if W=8
8 week+ 8 days= 56 days + 8 Days= 64
8W= 8x8=64

I hope its clear now