Akash and Sita went to Varanasi during their holidays. Sita wanted to visit all
the ghats of Varanasi. So, they hired a motorboat for this purpose. While riding,
Akash observed that the speed of motorboat was 20 kmph. He was curious to
know the speed of river ganga. So he noted the time taken by the boat to travel
upstream and downstream in the river. He noticed that the boat took 1 hr more
to travel upstream than downstream to cover a distance of 15 km.
Based on the above information, answer the following questions:
i) If the speed of the river is x kmph, then the upstream speed of
the motor boat will be?