Given
Lee converted 500 U.S. dollars to 625 Singapore dollars.
x represents U.S. dollars and s represents Singapore dollars.
Find out equations represents the relationship between the two currencies.
To proof
As given in the question
x represents U.S. dollars and s represents Singapore dollars.
converted 500 U.S. dollars to 625 Singapore dollars
500 x = 625 s

x = 1.25 s
This shows that the U.S dollars is equal to 1.25 times of singapore dollars.
Hence proved