2015 AMC 10B Problem 4

Below is the professionally curated solution for Problem 4 of the 2015 AMC 10B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2015 AMC 10B solutions, or check the answer key.

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Concepts:fraction

Difficulty rating: 960

4.

Four siblings ordered an extra large pizza. Alex ate 15,\frac15, Beth 13,\frac13, and Cyril 14\frac14 of the pizza. Dan got the leftovers. What is the sequence of the siblings in decreasing order of the part of the pizza they consumed?

Alex, Beth, Cyril, Dan

Beth, Cyril, Alex, Dan

Beth, Cyril, Dan, Alex

Beth, Dan, Cyril, Alex

Dan, Beth, Cyril, Alex

Solution:

Since 13>14>15,\frac 13 > \frac 14 > \frac 15, we know Beth ate more than Cyril and Cyril ate more than Alex. Thus, those three are in order.

The amount Dan ate is 1131415=1360.1- \dfrac 13 - \dfrac 14 - \dfrac 15 = \dfrac{13}{60}. This is greater than 15\frac 15 and less than 14,\frac 14 , so Dan is in between Cyril and Alex. This makes the order Beth, Cyril, Dan, Alex.

Thus, the correct answer is C .

Problem 4 in Other Years