H and A start a two-length swimming race at the same moment but from opposite ends of the pool.they swim in lane and at uniform speeds,but H is faster than A.They first pass at a point 18.5m from the deep end,and having completed one length.each one is allowed to rest on the edge for exactly 45 secs. After setting off the return length,they pass for the second time just 10.5m from the shallow end. how long is the pool?