Each nurse buys a gift for another nurse in a
hospital. how many nurses are there in the
hospital, if 72 gifts bought in total

9

Steps:

Each nurse must buy x-1 gifts where x is the number of nurses (since she does not buy a gift for herself). Therefore, the total number of gifts purchased would be the number of nurses multiplied by the number of gifts each nurses has to buy, giving us the equation;

x * (x - 1)

Which simplifies to;

x^2 - x

Then we set this equal to 72;

72 = x^2 - x

And using guess and check (because to be honest it’s 1 AM and I can’t think of the proper way to solve it) we get x = 9