Mathematics · Shortest Distance

Rohit starts from Point A and walks 20 m towards the north. He takes a left turn, walks 35 m and then takes a left turn, walks 10 m, then takes a left turn, walks 40 m, reaches Point B and stops. Mohan starts from Point Z which is 40 m towards the north of Point A. He walks 30 m towards the east, takes a right turn, walks 40 m, and stops at Point X. What is the shortest distance between Point X and Point A? (All turns are 90-degree turns only.)