A jar contains black and white marbles. If there are ten marbles in the jar, then which of the following could not be the ratio of black to white marbles?

Question: A jar contains black and white marbles. If there are ten marbles in the jar, then which of the following could not be the ratio of black to white marbles?

Solution:
Since the number of black and white marbles are whole numbers,
So the sum of the terms of the ratio must be a factor of 10.
ক) 1:4 = 1+4 = 5 a factor of 10.
খ) 1:10 = 1+10 = 11 not a factor of 10.
গ) 7:3 = 7+3 =10 a factor of 10.
ঘ) 9:1 = 9+1 = 10 a fac tor of 10.

Here we can see that the sum of only the second option is not a factor of 10