Let $$A(x)=x\sum_{p \leq x} 1, B(x)=\frac{3}{5}\sum_{x
Let $$A(x)=x\sum_{p \leq x} 1, B(x)=\frac{3}{5}\sum_{x
The sum of the primes up to $x$ is, asymptotically, $(1/2)x^2/\log x$. So asymptotically, $$B(x)=(3/5)((1/2)(2x)^2/\log(2x)-(1/2)x^2/\log x))$$ Looks like about $(9/10)x^2/\log x$.