Question :
"A club has raised 75% of the amount it needs for a new building by receiving an average donation of ₹ 600 from the people already solicited. The people already solicited represents 60% of the people the club will ask for donations. If the club is to raise exactly the amount needed for the building, what should be the average donation from the remaining people to be solicited?"
I am literally unable to touch pen on paper in this problem.
Here's a strategy for touching pen to paper.
Start by supposing the club has $100$ members.
How many people have been solicited?
Use that to figure out how much money the club has raised.
Figure out how much they need in total, and then how much more they need.
How many people must they get that from?