there are 40 marbles in a jar. Chris had 2/5 of the marbles, Sal had 1/8, Tim had 1/10, and Bob, John and Don split whatever was left over evenly. How many marbles did Bob, John and Don split ?

2/5 * 40 = 80/5 = 16

1/8 * 40 = 40/8 = 5

1/10 * 40 = 40/10 = 4

40 - 25 = ?

To find out how many marbles Bob, John, and Don split, we first need to determine the total number of marbles that Chris, Sal, and Tim had together.

Chris had 2/5 of the marbles, which can be calculated by multiplying the total number of marbles (40) by 2/5:
2/5 * 40 = 16 marbles

Sal had 1/8 of the marbles, which can be calculated by multiplying the total number of marbles (40) by 1/8:
1/8 * 40 = 5 marbles

Tim had 1/10 of the marbles, which can be calculated by multiplying the total number of marbles (40) by 1/10:
1/10 * 40 = 4 marbles

To find out how many marbles Bob, John, and Don split, we need to subtract the sum of Chris, Sal, and Tim's marbles from the total number of marbles:

Total number of marbles - (Chris' marbles + Sal's marbles + Tim's marbles) = Marbles split by Bob, John, and Don

Therefore, Bob, John, and Don split:
40 - (16 + 5 + 4) = 40 - 25 = 15 marbles.

So, Bob, John, and Don split 15 marbles.