For 226, the angles or the mass is not important. The question does not state anything about it being on an angle. Hence, we assume that there is no angle - it is horizontal.
Secondly, I like to do questions like these using change in energy equations. We know that it started off with a kinetic energy dictated by its mass and velocity (20m/s).
We know that friction was working against it till it had ZERO kinetic energy. Therefore, the change in energy is work done by friction = initial kinetic energy of the car.
Work equation due to friction is (Ffriction)(d) - now further elaborated, Ffriction is equal to (m)(g)(mu) because force of friction is normal force times coefficient of kinetic friction (mu). Hence, work equation is (m)(g)(mu)(d)
The kinetic energy equation is 0.5mv^2.
Now, we equate them to each other like so:
(m)(g)(mu)(d) = 0.5mv^2
We see that the masses cancel out! :)
So, we get (10)(0.1)(d) = 0.5(20^2)
d = 200.

Now, for 227, since we have displacement and velocity from the previous question, we can figure out time :)

Hope this helps! :)
And so, we are left with (10)(0.1)