Cash price: $32,000 Down payment: $6,900
Monthly payment: $518
Number of payments: 60
Installment charge: ?

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

It is 5.8 you add all of the up to equat 180 then solve the equation