$80 - Diane: green ($50) and orange ($30)
$60 - Emily: blue ($40) and red ($20)
$60 - Alice: green ($50) and yellow ($10)
$50 - Betty: orange ($30) and red ($20)
$50 - Carol: blue ($40) and yellow ($10)
There are five colors of shirts in $10 increments, with the most expensive costing $50, meaning that they cost 10, 20, 30, 40 and 50 dollars in some order. Since each girl bought two different shirts, possible totals are:
$30 = 10 + 20
$40 = 10 + 30
$50 = 10 + 40
$50 = 20 + 30
$60 = 10 + 50
$60 = 20 + 40
$70 = 20 + 50
$70 = 30 + 40
$80 = 30 + 50
$90 = 40 + 50
Since Diane spent the most, and the other two pairs of girls spent the same amounts [1], possible triples of the amounts spent are, at first glance:
50, 60, 70 (10,40;20,30;10,50;20,40;20,50)
50, 60, 70 (10,40;20,30;10,50;20,40;30,40)
50, 60, 80 (10,40;20,30;10,50;20,40;30,50)
50, 60, 90 (10,40;20,30;10,50;20,40;40,50)
50, 70, 80 (10,40;20,30;20,50;30,40;30,50)
50, 70, 90 (10,40;20,30;20,50;30,40;40,50)
60, 70, 80 (10,50;20,40;20,50;30,40;30,50)
60, 70, 90 (10,50;20,40;20,50;30,40;40,50)
However, we are also told that two of each color shirt were bought, eliminating most of the above combinations (the underlined priced appear three times, and the italicized values appear only once in the invalid combinations). The only valid result (in bold), then, is that Diane spent $80, while the other pairs of girls spent $50 and $60 on their clothes, respectively:
80 = 30 + 50 (Diane)
60 = 20 + 40
60 = 10 + 50
50 = 20 + 30
50 = 10 + 40
We know that Diane spent $80 on thirty- and fifty-dollar shirts, and Emily did not buy any shirts of the same colors as she did [3]. Thus, Emily either spent $10 and 40 or $20 and 40, and we know for sure that she did buy a forty-dollar shirt. Also, we are told that Carol bought the other forty dollar shirt [5]:
80 = 30 + 50 (Diane)
60 = 20 + 40 (Emily/Carol)
60 = 10 + 50 (Alice/Betty)
50 = 20 + 30 (Alice/Betty)
50 = 10 + 40 (Emily/Carol)
Carol didn't buy a twenty-dollar shirt with Alice [4]; it must have cost ten dollars [5], and by elimination, we know what price shirts everyone bought:
80 = 30 + 50 (Diane)
60 = 20 + 40 (Emily)
60 = 10 + 50 (Alice)
50 = 20 + 30 (Betty)
50 = 10 + 40 (Carol)
Now, to match prices to colors:
Carol's blue shirt was not ten dollars [2]; it must have been forty dollars. The ten-dollar shirt was not green [2], orange [4], or red [5]; it must have been yellow:
$10: yellow
20
30
40: blue
50
Alice and Betty did not buy any shirts in common [above], so Alice's fifty-dollar shirt was not yellow [$10], blue [$40], orange [4], or red [5]; it was green.
$10: yellow
20
30
40: blue
50: green
By elimination, Betty's twenty- and thirty-dollar shirts were red and orange, in some order. Emily bought a twenty-dollar shirt, but it was not orange [4]; it must have been red. That leaves the orange shirt at $30:
$10: yellow
20: red
30: orange
40: blue
50: green
So, to recap:
$80 - Diane: green ($50) and orange ($30)
$60 - Emily: blue ($40) and red ($20)
$60 - Alice: green ($50) and yellow ($10)
$50 - Betty: orange ($30) and red ($20)
$50 - Carol: blue ($40) and yellow ($10)
Taken from DJ's solution here.
Charlie shows how the program is accomplished through a program here. |