Challenging algebra problem

Dear Sir .

I need some help in the below questions .

Thanks very much

1) When Tom came to London, Kathy was as old as Baba and Tom together.

How old was Tom when Kathy was as old as Baba was when Tom came to London?

2)A swimmer was swimming upstream River A. Near the Bridge R he lost

A ball. After swimming 20 min more upstream he noticed his loss and

swam back to find the ball; he reached it near the Bridge S. Find the

velocity of current at River A if the distance between these two bridges

is 2 km. (Ans: 3 km/h).

How far has the swimmer travelled before he turned back to prick uo the ball.

A schematic diagram can be helpful.