###Human: A cake of 400 grams is divided into eight equal parts. Nathalie eats one-eighth of the cake, and Pierre eats double what Nathalie ate. How much did Pierre eat, in grams?, ### Assistant: Nathalie ate 1/8 * 400g = 50g of cake.
Pierre eats 2 * 50g = 100g of cake. 
 So the answer is :  100