<span>Let the total hour of exam is 3hrs ie 180 minutes.( since answer required in minutes).
Let as assume maths questions be in x minutes.
Let the assume rest of the question is in y minutes.
Given that out of 320 qns 40 is maths qns.
therefore, maths qn is =40 and rest of qns is 280.
Also given the time of maths qns is twice of rest. They related in the following equation. ie x:y=2:1 ; x/y =2/1
ie x=2y
therefore 2x+y= 180 min ; ie 2(2y)+y= 180 ; y=36
therefore resolving for x = 2*36 = 72
time spent for maths qn is 2*x = 2* 72 =144min.
rest of maths question is 36 min.</span>
