At 1pm 12 birds we’re on the beach at 3pm 40 birds were on the beach whats the constant rate of change

I got the rate of change as 14 birds per hour.

I found the rate of change by using two coordinates, (1,12) and (3,40). I then used the slope formula, y2-y1/x2-x1 while plugging in the values with the two given coordinates. After simplifying I got 14 birds per hour.

(Please check my method to see if the answer I got is correct)