• # question_answer The number of non negative integral solution of the equation, $x+y+3z=33$ is: A) 120 B) 135 C) 210 D) 520

 Consider cases when z = 0, 1, 2,....... 11 $\Rightarrow$$34+31+28+.....+1\,(12\,\,time)=\frac{12}{2}(1+34)=210$