Question 884159
Previously it cost {{{500X}}} to buy 500 cans. 
Now that the price is {{{0.75X}}} 500 cans only cost, {{{500(0.75)X=375X}}}
So you have {{{500X-375X=125X}}} left over.
Then you can buy an extra Y cans.
{{{Y=125X/(0.75X)=166.7}}} cans.
Since you can only buy an integer number of cans, you can buy an extra 166 cans which makes a total of 666 cans.