For A to catch B, A must travel (193 +x) meters if B travels x meters, both spending the same amount of time.

Distance = speed * time

So, time = distance / speed

t1 = t of A = (193 +x)/27.1

t2 = t of B = x/18.6

t1 = t2

(193 + x)/27.1 = x/18.6

Cross multiply,

(193 +x)(18.6) = 27.1(x)

193(18.6) +18.6x = 27.1x

193(18.6) = 27.1x -18.6x = 8.5x

x = (193*18.6)/8.5 = 422.33 m

Hence,

t = t1 = (193 +422.33)/27.1 = 22.7 sec

t = t2 = 422.33/18.6 = 22.7 sec

Therefore, after 22.7 seconds, A will catch up with B. -----answer.