Bishan cycled 120 km at a fixed speed. Had he cycled 3 km/hr slower, he would have taken 2 hours more to reach the destination. Find his actual speed in km/hr.

1. Let actual speed be v. Then 120/(v−3) − 120/v = 2. 2. Testing v = 15: 120/12 − 120/15 = 10 − 8 = 2 hours. 3. The condition is satisfied, so actual speed = 15 km/hr. _Source: RRB Group D CEN-02/2018 PYQ, Q.78._