Points O, A and B lie in that order on a straight line. A particle P is moving on the line with S.H.M period of 4s, amplitude 0.5m and centre O. OA is 0.1m and OB is 0.3m. When t = 0, P passes through B travelling in the direction OB. Calculate the time when P passes A

I tried using the following equation to find the first part of the motion, B to amplitude.

X = a Sin(wt + 0.3)

0.2 = 0.5 Sin(0.5Pi t + 0.3)

and for the second part of the motion, amplitude to A:-

0.4 = 0.5 Cos(wt)

However i get nowhere near the correct answer of 1.46s when i add the two times together.

Any help would be greatly appreciated,

Thanks,

Rob