Just trying to answer logically.
If you consider first node from A, there are 4 possible ways to reach B. So from A there are 4 nodes at level 1, which means total number of ways to reach B is 16.

Ramesh’s father is a paediatrician. Ram’s father is a trader. Krishan’s father is a school teacher. Krishan falls ill. Where should his father take him? to home to school to Ramesh’s father to Ram’s father

Five people are standing in a row. Aman is standing next to Karan but not adjacent to Tanuj. Radhika is standing next to Priyanka who is standing on the extreme left and Tanuj is not standing next to Radhika. Who are Standing adjacent to Aman? Radhika and Karan Karan and Tanuj karan and Priyanka Radhika and Tanuj

If $5\%$ income of P is equal to $15\%$ income of Q and $10\%$ income of Q is equal to $20\%$ income of R. If income of R is $₹ 2000$, then what are the incomes of P and Q respectively? ₹$4000$ and ₹$8000$ ₹$12000$ and ₹$4000$ ₹$15000$ and ₹$5000$ ₹$18000$ and ₹$6000$