N2013 P2 Q6

The continuous random variable \(Y\) has the distribution \(N\left( \mu ,{{\sigma }^{2}} \right)\). It is known that \(\mathrm{P}\left( Y<2a \right)=0.95\) and \(\mathrm{P}\left( Y<a \right)=0.25\). Express \(\mu \) in the form \(ka\), where \(k\) is a constant to be determined.[4]