1.The average of four men is x, so their overall score is 4x
When a new man comes their average score is x+3, so the overall score is (x+3)*4= 4x+12
If we compare the overall score before (4x) and the overall score now (4x+12) it becomes clear, that the new guy's score is higher by 12 points than the score of the man before him, so 120+12= 132 points.
The answer is: the new man's marks are 132 points.
2.His average before= x
His overall score before= 16x
His average score now=x+3
His overall score now=(x+3)*17=17x+51
34=x (his average score before)
His average score now is 34+3=37
I think it's ok