momentum question

The diagram below shows two balls on the bowling green. Ball A is moving with a velocity of 4 m/s and is about to collide with ball B which is stationary. Both balls have a mass of 1.5kg.

A 4 m/s -----> B

After the collision both balls move to the right but the velocity of A is now 1 m/s.

a) (i) Calculate the momentum of ball A just before the collision in kg m/s
i get that this part would be 6kgm/s
(ii) What is the total momentum of balls A and B after the collision in kg m/s?
and that this would also be 6kgm/s
(iii) Calculate the momentum of ball A just after the collision in kg m/s
but the answer for this is meant to be 1.5 kgm/s and i dont understand why

The velocity of A after the collision is 1 m/s

"After the collision both balls move to the right but the velocity of A is now 1 m/s."

Mass is 1.5kg

so momentum is 1.5kgm/s