A boat moves with velocity vB=10i^+6j^km h−1 with respect to the ground, while the river water flows with velocity vR=3i^−4j^km h−1. Determine the velocity of the boat relative to the river, vBrelR.
(a) 13i^+2j^km h−1
(b) 7i^+10j^km h−1
(c) −7i^−10j^km h−1
(d) 7i^+2j^km h−1