Sabrina walks at 8 km/h and cycles at 13 km/h. She covers 84 km in 8 hours in total. For how many hours did she cycle?

1. Let cycling hours = c, then walking hours = 8 − c. 2. Distance: 13c + 8(8 − c) = 84 → 5c + 64 = 84. 3. 5c = 20, so c = 4 hours. _Source: RRB Group D CEN-02/2018 PYQ, Q.52._