On a snow day, Nolan created two snowmen in his backyard. Snowman A was built to a height of 31 inches and Snowman B was built to a height of 52 inches. The next day, the temperature increased and both snowmen began to melt. At sunrise, Snowman A's height decrease by 4 inches per hour and Snowman B's height decreased by 7 inches per hour. Let AA represent the height of Snowman A tt hours after sunrise and let BB represent the height of Snowman B tt hours after sunrise. Write an equation for each situation, in terms of t, t, and determine the interval of time, t, t, when Snowman A is taller than Snowman B.