A 40 kg cart is moving on a level ground at 10 m/s wgeb work is done upon it in such a way that its kinetic energy doubles. How much work was done on the cart?

For this I got 6000J

The second half of this question I'm not sure how to approach.
The cart mentioned about is now sent up a frictionless ramp how high does it climb before it comes to a stop?

Please help

The kinetic energy when the cart starts is

E_k=\frac12 mv^2=2000J

If you double it to 4000J, you've added 2000J of energy, which means you must have done 2000J of work.

For the second part, now that the cart has 4000J of kinetic energy, all of that will be converted to gravitational potential energy as it goes up the ramp. Hence you set beginning kinetic energy to the final gpe:

4000=mgh

and solve for h.