The volume of water in a vessel was 8 L at 2:00 p.m. It changed by −3 L after an hour. What was the volume at 3:00 pm?

For number 11 think of them as decimals and1/2 is .5 and on 12 put them all in as decimals and figure it out and on 13 divide 1/4 and it will get you .25 and add the 6 and the rest all the same rules apply and you just have to figure out which one it is