Could I get a longer wrench please?

The bolt/nut system is no different than an inclined plane - it's just an inclined plane wrapped around a cylinder. Since you need to rotate the nut N times in order to move the distance d, the outer edge of the bolt needs to spin in the nut a total distance of $2 \pi N R$ . This is the same with an inclined plane of inclined angle $x = \arcsin{d/2\pi N R}$ that “wraps” around the bolt’s axis. The force between the bolt hat and the nut is equal to F, which means there’s a force parallel with the bolt axis that pushes the bolt into the nut.

The normal force acting on the inclined plane is $N=Fcos(x)$ and the maximum friction force plus the component of F along the inclined plane is $F_r=kN-Fsin(x)=F(kcos(x)-sin(x))$ , so in order to unfasten the bolt/nut system, you need to overcome the force $F_r$ . When you put a torque $M$ on the nut, it is equivalent in the inclined plane picture to an extra force $Q = M/R$ in the horizontal direction. The total force you need to overcome is $F_r + kMsin(x)/R= F(kcos(x)-sin(x)) + kMsin(x)/R$ along the plane:

$F(kcos(x)-sin(x)) + kMsin(x)/R \leq Mcos(x)/R$

$\Rightarrow M_{min}= FR(kcos(x)-sin(x))/(cos(x)-ksin(x))$

Plug in the numerical values and you get the answer!