Answer:
The boy's acceleration toward the girl is 2.08 m/s^2.
Step-by-step explanation:
According the Newton's Third Law, the force causing the girl accelerate towards the boy will be me with equal counter-force causing the boy to accelerate towards the girl. These forces will be of equal magnitude and allows us to determine the boy's acceleration:

The boy's acceleration toward the girl is 2.08 m/s^2.