Answer
$190.2\space m/s$
Work Step by Step
Please see the attached image first.
Let's apply the equation $F=ma$ to the aircraft.
$\angle15.4^{\circ}\space \nearrow F=ma$ ; Let's plug known values into this equation.
$F-193\space kN-138\times10^{3}gsin15.4^{\circ}\space N=0$
$F= (193+359)\space kN= 552\space kN$
Let's apply equation $P=FV$ to the aircraft.
$P=FV$ ; Let's plug known values into this equation
$105\space MW=552\space kN\times V$
$190.2\space m/s=V= Maximum\space speed\space of\space aircraft$
