Probability that the electron is found at a distance greater than r

The problem given is to calculate the probability that the electron is found at a distance greater than r=2a0 from the center of the hydrogen atom in its ground state.

I don't understand what the problem is asking. I dont understand what form of the wavefunction I should use.

I know that to calculate the probability is P(r)= abs value (ψ(r))^2 or P(r)= ψ*(r).ψ(r)

but what wave function should i use in this problem? should i use e^(r/a0)/sqrt(pi.a0)?

i know that at the ground state n=1 in which makes n,l=0

 

Thank you!