PhysicsEasy65×since 2002Q7827A vehicle travels 4 km4 \mathrm{~km}4 km with speed of 3 km/h3 \mathrm{~km} / \mathrm{h}3 km/h and another 4 km4 \mathrm{~km}4 km with speed of 5 km/h5 \mathrm{~km} / \mathrm{h}5 km/h, then its average speed isA3.75 km/h3.75 \mathrm{~km} / \mathrm{h}3.75 km/hB4.25 km/h4.25 \mathrm{~km} / \mathrm{h}4.25 km/hC3.50 km/h3.50 \mathrm{~km} / \mathrm{h}3.50 km/hD4.00 km/h4.00 \mathrm{~km} / \mathrm{h}4.00 km/hCheck answerSkip