Refer to map and answer the following question:

Each centimetre on the map, as printed here, represents a certain distance on the ground — let us suppose it is$500$ metres; we say that the scale is $1$ cm = $500$m. Now, turn to the map of India given above. The scale is represented in the bottom left corner by a ruler with $‘500$’ written above its length and ‘km’ on the side. It simply means that this ruler, which measures$2.5$ cm in the printed map, corresponds to $500$ kilometres on the ground.

Taking the scale to be $2.5$ cm = $500$ km, calculate the real distance from the estuary of the Narmada River to the estuary of the Ganga river. (Hint: round off your measurement on the map to an easy number.)