I have 7 bags of marbles. There are 200 marbles in total. Using the clues below, work out how many marbles there are in each bag.
Bag 1 + Bag 2 = 57 marbles
Bag 2 + Bag 3 = 83 marbles
Bag 3 + Bag 4 = 71 marbles
Bag 4 + Bag 5 = 43 marbles
Bag 5 + Bag 6 = 66 marbles
Bag 6 + Bag 7 = 43 marbles
Answer
Bag 1 = 31 marbles
Bag 2 = 26 marbles
Bag 3 = 57 marbles
Bag 4 = 14 marbles
Bag 5 = 29 marbles
Bag 6 = 37 marbles
Bag 7 = 6 marbles
If you know that Bag 1 + Bag 2 = 57 marbles, and Bag 3 + Bag 4 = 71 marbles, and Bag 6 + Bag 7 = 43 marbles, then you should be able to work out the amount of marbles for Bag 5. 200-57-71-43=29, so Bag 5 has 29 marbles. From that you can work out that Bag 4 has 14 marbles and Bag 6 has 37. From that you can work out that Bag 3 has 57 marbles and that Bag 7 has 6 marbles. From that you can work out that Bag 2 has 26 marbles and from that you can work out that Bag 1 has 31 marbles.