Answer:
23 marbles
Step-by-step explanation:
Number of children = 10
Number of marbles = 180
Since Betsy gets the most and no 2 children gets the same number of marbles
The least number of marbles Betsy could get will be x ; with the other 9 children receiving 1 less each
That is :
Betsy = x
9th child = x - 1
8th child = x - 2,... 1st child = x - 9
Hence,
(x + x - 1 + x - 2 + x - 3 + x - 4 + x - 5 + x - 6 + x - 7 + x - 8 + x - 9) = 180
10x - 45 = 180
10x = 180 + 45
x = 225 / 10
x = 22.5
x = 23
Hence, the least Betsy could get is 23 marbles
