The ratio of the number of marbles in Box A to that in Box B is 3:7.Box B has 12 more marbles than Box A.(a) How many marbles are there altogether?(b) If 3 marbles are moved from Box A to Box B, what will be the new ratio of the marbes in Box A to that in Box B?

There are 8 total "parts" of marbles, 3 in box A and 5 in box B. The 2-part difference is 10 marbles, so each part is 10/2 = 5 marbles.

1. There are 8(5) = 40 marbles altogether.

2. Box A starts with 3(5) = 15 and Box B starts with 5(5) = 25. If we move 3 from A to B, we now have a ratio of 22:28. Reduced, that's 11:14.

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