September 22, 2015

Problem of the Week

for Tuesday September 22, 2015

Teri sells fruit in Tetraville. She stacks her oranges in a display that mimics the great tetrahedral pyramids of her hometown. Below you see the top two layers of her display. How many oranges does she need if she wishes to stack her pyramid six levels high and have every layer be an equilateral triangle of oranges?

Winners of the Tetraville challenge