When an $\alpha$ -particle with kinetic energy K = 11 MeV collides with a stationary lithium nucleus, the following nuclear reaction takes place
  ${ }^{4}He{+}^{7}Li{\to }^{10}B+n$
The Q-value of this reaction is E = -2.86 Mev. If the kinetic energy of the neutron outgoing at right angle to the incoming direction of $\alpha$ -particle is X MeV and the kinetic energy of boron atom is Y MeV.