PreparationMock TestRRBFree Online RRB SSE Stage 1 Mock TestBy salma A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is?(A) 7 km/h(B) 5 km/h(C) 3 km/h(D) 2 (1/2) km/h