Answer:
The amount of money in his paycheck was $ 225.
Explanation:
Given that Li put $ 75 into his savings account, and said money was 1/3 of his paycheck, to determine which equation could be used to find the amount of money, p, in dollars, on his paycheck, the following reasoning must be performed mathematical: 
 
75 / (1/3) = P 
75 / 0.333 = P 
225 = P 
 
Thus, the amount of money in his paycheck was $ 225.