Question 946761
Try to think through the problem description as a process.


The 25% discount means, remove {{{25/100}}} of $420 from $420, and only pay the 75% or {{{75/100}}} of the $420 which remains.  The quantity that was removed is the quantity which you do not pay.


You would save {{{(25/100)(420)=(1/4)(420)}}}  dollars.