it will be 20
as it is symmetrical on both side of graph
and have two roots on either side of
0.5+n(2)
as long as it is<10
you can see it has 5 values
so roots are
5*2=10
and as it is symmetrical
so 10*2=20

 

 

here is the graph if I am right

this is only positive part and the extreme right seems to concide but it is just an illusion

ans=10

for one side