Recall the formula for kinetic energy.

The kinetic energy (K.E.) of an object is given by the formula:

$$K.E. = \frac{1}{2} m v^2$$

where $m$ is the mass and $v$ is the speed.

Multiply both sides by 2:

$$2 K.E. = m v^2$$

Divide both sides by $m$:

$$v^2 = \frac{2 K.E.}{m}$$

The problem states that the car and the truck have the same kinetic energy. This means K.E. is constant for both vehicles. Also, 2 is a constant.
Therefore, we can see that $v^2$ is inversely proportional to $m$:

$$v^2 \propto \frac{1}{m}$$

This implies that if the mass ($m$) is smaller, the speed squared ($v^2$) must be larger to maintain the same kinetic energy. Consequently, the speed ($v$) will also be larger.

We are given that the truck has more mass than the car.
Since $v^2 \propto \frac{1}{m}$, the object with less mass will have a greater speed.
The car has less mass than the truck.

Therefore, the car has greater speed.

The car has greater speed.

$$\text{The car}$$