
This is a trial paper question I found. It's like one of the only motions questions that has me confused. I don't get why Swimmer X is relevant in this situation? Are they swimming with a rope attached to eachother or something. I just tried to let the Y component (North South Vector) be in equilibrium. But the solutions labelled this as a common error?

For reference, if anyone could decipher what they've written, this is their solution.

Thanks i'm genuinely baffled on what they have done so much appreciated if someone could help explain.