1011. Solving a chemistry problem

9. In a sample of synthesized gold nanoparticles, the particle diameter is distributed approximately normally, with an arithmetic mean x and with a standard deviation s indicated in the table below for the corresponding problem number. Calculate (for your problem number) the fraction of particles in the sample whose diameters are in the range from x1 to x2, taking µ= x and σ=s.
Problem number x/nm s/nm x1 /nm x2 /nm
9 8.8 3.1 5.7 11.9