A transverse wave on a string is described by the following equation.

y(x, t) = (0.35 m) sin[(1.25 rad/m)x + (81.2 rad/s)t]

Consider the element of the string at x = 0.

(a) What is the time interval between the first two instants when this element has a position of y = 0.247 m?
(in miliseconds)

(b) What distance does the wave travel during this time interval?
(in meters)