A student bought a smartwatch that tracks the number of steps she walks throughout the day. The table shows the number of steps recorded t minutes after 3:00 p.m. on the first day she wore the watch. t (min) 0 10 20 30 40 Steps 3,338 4,609 5,522 6,486 7,218 (a) Find the slopes of the secant lines corresponding to the given intervals of t. (1) [0, 40] (1) [10, 20] (lil) [20, 30] (b) Estimate the student's walking pace, in steps per minute, at 3:20 p.m. by averaging the slopes of two secant lines from part (a). (Round your answer to the nearest integer.) steps per minute