a person walks at a speed of 4 km / hr and runs at a speed of 8 km / hr . how many hours will the person require to cover a distance of 4 km , if the person completes half of the distance by walking and the other half by running ?
"time = 2 / 4 + 2 / 8 = 6 / 8 = 0.75 hours the answer is c ."
add(divide(divide(4, const_2), 4), divide(divide(4, const_2), 8))