Mr Tan had $20 more than Mr Lee at first. After Mr Tan spent $50 and Mr Lee spent half of his money, both of them had the same amount of money left. How much money did Mr Lee have at first? Ans: $ ___

1. Set up the relationship between Mr Tan's and Mr Lee's money at first

Let Mr Lee's money at first be $2u$.
Mr Tan's money at first = $2u + 20$.

2. Express the amount of money left for both

Mr Lee spent half his money, so he had $1u$ left.
Mr Tan spent $\char36{}50$, so he had $(2u + 20) - 50 = 2u - 30$ left.

3. Equate the remaining amounts to find $u$

Since they had the same amount left:
$2u - 30 = 1u$
$u = 30$

4. Calculate Mr Lee's initial amount

Mr Lee's money at first = $2u = 2(30) = 60$.