To simplify the expression 105/10 : 10/105, you first need to convert the division of fractions into a multiplication of fractions by taking the reciprocal of the second fraction.
105/10 : 10/105 = 105/10 * 105/10
Now, you can simplify this expression by multiplying the numerators together and the denominators together:
(105 * 105) / (10 * 10) = 11025 / 100 = 110.25
Therefore, 105/10 : 10/105 = 110.25.