A computer shop charges ₱20.00 per hour ( or a fraction of an hour) for the first two hours and an additional ₱10.00 per hour for each succeeding hour. Find how much you would pay if you used one of their computers for 150 minutes

well, 150 minutes = 2.5 hours

so charge = 2(20) + 10 , assuming the second rate also is per hour, or a fraction of an hour
= 50