Numerical answer type, answer in %, tolerance 0.6.
Answer: 38 %
Mulliken values are (5.2+0.5)/2=2.85 eV for M and (12.0+3.3)/2=7.65 eV for X. On the Pauling scale these are 1.018 and 2.732, so Δχ=1.714. Percent ionic character =16(1.714)+3.5(1.714)2=27.4+10.3=37.7, i.e. 38.