thnk ulet p's time = t
then q's time = t - 2
a = 1.75 and u = 0 for both
Displacement of P = 0.875t^2
Displacement of Q = 0.875(t-2)^2
Displacement of P - Displacement of Q = 4.9
0.875t^2 - 0.875(t-2)^2 = 4.9
t = 2.4
but since it's talking about time in terms of Q in the question
t = 2.4 - 2
= 0.4