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?
Nathalie ate 1/8 * 400g = <<1/8*400=50>>50g of cake.
Pierre eats 2 * 50g = <<2*50=100>>100g of cake.
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