The coloring takes 2*.3=<<2*.3=.6>>.6 hours less than the drawing
So it takes 2-.6=<<2-.6=1.4>>1.4 hours per picture
So it takes him 2+1.4=<<2+1.4=3.4>>3.4 hours per picture
That means it takes 3.4*10=<<3.4*10=34>>34 hours
#### 34