41. In how many ways can 5 people be seated in a row so that Kolya and Olya sit next to each other?
41. First, let's seat Kolya and Olya. There are 4 ways to seat them next to each other with Olya sitting to the right of Kolya, and 4 ways with Olya sitting to the left of Kolya. Thus, for 5 free seats, there are 8 ways to seat Kolya and Olya next to each other. After seating Kolya and Olya, 3 seats will remain free. These can be occupied in $3!=6$ ways. Therefore, the total number of ways to seat 5 people will be $8 \cdot 6=48$.