15:(6:2)

To simplify the expression \( 15:(6:2) \), we need to first solve the operation inside the parentheses.

1. Calculate \( 6:2 \): \[ 6:2 = 3 \]

2. Now replace \( 6:2 \) with \( 3 \) in the original expression: \[ 15:3 \]

3. Finally, calculate \( 15:3 \): \[ 15:3 = 5 \]

Therefore, the result of the expression \( 15:(6:2) \) is \( 5 \).