If two distinct planes intersect, then their intersection is a line. If two distinct lines intersect, then they intersect in exactly one point. If there is a line and a point not in the line, then there is exactly one plane that contains them. If two distinct lines intersect, then they lie exactly in one plane.
now, bear in mind, the yellow is a bucket and 1/3 more, the green one is one bucket and 1/4 more and the blue is 7/8 which is almost 8/8, so is almost a bucketfull.
Then he's going to use 3/4 of each, so, we'd have to subtract 3/4 from each, and there'll be some left still in the paint bucket.
How many will he have left altogether? well, we simply add the leftovers.