Question: Pete has a bag with 10 marbles. 40% are blue and the rest are red. His friend will trade him two blue marbles for every red one. If Pete keeps 1 red marble, how many total marbles does he have after trading with his friend? Think carefully first, then make a decision:
He starts with 4 blue marbles because 10 x .4 = 4. 60% of the marbles are red because 100 - 40 = 60. He has 6 red marbles because 10 x .6 = 6. He trades 5 red marbles because 6 - 1 = 5. He gets 10 blue marbles because 5 x 2 = 10. He has 15 marbles now because 4 + 1 + 10 = 15. So the answer is 15.