The total number of questions = 200
In which, Mathematics, G.K and Science has 50, 100 and 50 numbers of questions, respectively.
Total time = 3 hours = 180 minutes
Time taken by Gita to solve question of G.K. and science = x
Time spent on Mathematics questions = 2x.
According to the statement,
150(x)+50(2x)=180 150x+100x=180 250x=180 x==0.72 minute.
Time spent by Gita on Mathematics questions = 50.
(2x)=50(2×0.72)=72 minutes.