Please answer the following question by reasoning step-by-step.
A football club has a balance of $100 million. The club then sells 2 of its players at $10 million each, and buys 4 more at $15 million each. How much money is left in the club register in millions of dollars?

60
The 2 players are sold for a total of 2 * 10 = $20 million.

So the club has 100 + 20 = $120 million.

The cost of buying 4 more players at $15 million each is 4 * 15 = $60 million.

So the club now has 120 – 60 = $60 million.

.

Thus, the answer is 60