In the figure, P is the starting point of Perter.
Q is the point of his first right turn which is 5m from the starting point.
R is the next point of his right turn which is again 5m from P.
T is another right turn which is 20m from R.
U is the stop point which is 5m from T.
It is clear that P is the starting point and U is the stop point.
We need to find PU.
From figure, PU = ST but ST = RT - RS and RS = QP
Therefore, PU = RT - QP
PU = 20 - 5 = 15m.
Hence, he is 15m far from the starting point.
