well 100 ÷ 4 = 24 so 3/4 =75/100 and three hours before ten would be 7:00 then you take fourth minutes from the remainder ( 30 mins) and it had to go back an hour because you can't do 30-40 (don't stubtract in time but for this you can you just have to know that 60 mins= 1hr and don't EVER do this: 5:75 <- this is incorrect time.) umm... 6:50?