so there are 36 possible combinations with a pair of dice. the amount that add up to 6 is 5. 5/36=0.138888888888888(repeating) which to put in a percent is 13.9%. so the probability that the sum is 6 would be 13.9%.
but if the sum is already known to be less than 8 then that means there is only 21 possible rolls, so we would have 5/21 instead of 5/36. 5/21=0.238095(repeating) which to put as a percent is 23.8%
so the probability the sum will be 6 given that the sum is less than 8 is 23.8%
Hope this helps.
