Б) 4/15и 3/7

To add these two fractions, we need to find a common denominator. The least common multiple of 15 and 7 is 105.

Multiplying the numerator and the denominator of the first fraction (4/15) by 7, we get:

(4/15) * (7/7) = 28/105

Multiplying the numerator and the denominator of the second fraction (3/7) by 15, we get:

(3/7) * (15/15) = 45/105

Now that the two fractions have the same denominator, we can add them together:

28/105 + 45/105 = 73/105

Therefore, the sum of 4/15 and 3/7 is 73/105.