Out of three annual exams, each of maximum marks of 600, Lalit secured average marks of 55% and 60% in the first two exams. How many marks should Lalit score in 3rd test exam to make his overall average equal to 70%?

Total required marks in the three examinations = (3 x 600 x 70)/100 =1260
Marks secured in first examination = 55% of 600 = ( 600 x 55)/100 =330
Marks secured in second examination = 60% of 600 = ( 600 x 60)/100 =360
Thus, the required marks in third examination = 1260 - (330 + 360)
= 1260 - 690
= 570