In a 3 hour examination of 320 questions, there are 40 mathematics problems. if twice as much time should be allowed for each math problem as each of the other questions, how many minutes should be spent on math problems

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.