The total distance in inches a toy train moves varies directly with the time in seconds
let the distance d and the time t
so,
d = c * t , where c is the constant of proportional
when t = 16 seconds , d = 272 in
so,
272 = c * 16
c = 272/16 = 17
so, d = 17 * t
when d = 527 in, then solve for t
527 = 17 * t
divide both sides by 17
t = 527/17 = 31 seconds
so, the answer is the last option 31 seconds