Marc mixes blue and yellow paint to make his favorite shade of green, which he'll use to paint his house. He has 14 cans of blue paint and 20 cans of yellow paint when he starts. He wants the same green color every time he mixes, so the amounts of blue and yellow must always be proportional to the original mixture. On day 1, he mixes 4 cans of blue and 6 cans of yellow. On day 2, he mixes 6 cans of blue and 9 cans of yellow.