Question 1184363
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A 20% discount means they paid 80% of the usual price, or 4/5 of the usual price.<br>
So the usual price was 5/4 of what they paid.<br>
So the amount each one saved is the difference between 5/4 of what they paid and what they paid; that difference is 1/4 of what they paid.<br>
1/4 of what each one paid is $13.75.  Answer D.<br>
If the informal reasoning is too hard to follow, here is the same solution using formal algebra.<br>
The discounted ticket price was $55.<br>
The discounted price is 80%, or 4/5, of the usual price.  If x is the usual price, then<br>
{{{55 = (4/5)x}}}
{{{x = 55/(4/5) = 55*(5/4)}}}<br>
The amount each friend saved using the group discount is the difference between the usual price and the discounted price, which is<br>
{{{(5/4)55-55 = (1/4)55 = 55/4 = 13.75}}}<br>