Leo had 400 marbles in a jar. He packed the marbles with ten marbles in each pack, and he gave some of them to his two friends, Manny and Neil.  He gave Manny 1/4 of the number of packs of marbles, Neil received 1/8 of the number of packs of marbles, and he kept the rest. How many packs of marbles did Leo keep? Let's answer step by step:
Leo had 400 / 10 = 40 packs of marbles. He gave Manny 1 / 4 x 40 = 10 packs of marbles. And, Neil received 1 / 8 x 40 = 5 packs of marbles. Thus, Leo. gave a total of 10 + 5 = 15 packs of marbles. Therefore, Leo kept 40 - 15 = 25 packs of marbles. The answer: 25.