If the weights retained on the $2.36 \mathrm{~mm}, 1.18 \mathrm{~mm}, 600 \mu \mathrm{~m}$, and $300 \mu \mathrm{~m}$ sieves are $30 \%$, $35 \%, 15 \%$, and $20 \%$, respectively, of the total weight of an aggregate sample, then the fineness modulus of the sample is ___________ (rounded off to 2 decimal places).

Concrete of characteristic strength 30 MPa is required. If 40 specimens of concrete cubes are to be tested, the minimum number of specimens having at least 30 MPa strength should be