need help with math word problem

Question

A group of friends are enjoying the hot weather by spending some time at the beach. Some of the friends are in the water swimming, and the rest are lounging on the sand. One of the friends in the water says to those on the beach: “If one of you joins us, there will be twice as many of us as there are of you.” To this, one of the friends on the beach replies: “Yes, but if one of you joins us, there will be as many of us as there are of you.” How many friends are in the water and how many are on the beach?

Answer 1

Let x = number of friends swimming and y = number of friends not swimming

x + 1 = 2(y - 1)

y + 1 = x - 1

x - 2y = -3

x - y = 2

Subtract the equations to get -y = -5

So, y = 5 and x = 7.

Answer 2

1/2(sw+1)=b-1

b+1=sw

1/2(b+1+1)=b-1

b/2+1/2+1/2=b-1

b/2+1 =b-1

-b/2 =-2

b=4

sw=5