Will the cycle time change if another oven is added?

It

still takes the same amount of time, $10$

minutes, to load and bake a dozen cookie with a second oven. In that sense, the cycle time

will remain at $10$ minutes per dozen

after a second oven is added. However, when dealing with only single$-$dozen orders, since Kristen will be busy mixing and spooning for TWO ovens, she will become the new bottleneck. There the cycle time for the whole process becomes

$8$

minutes, which is the time Kristen spends mixing and spooning one dozen cookie. You can see from the following Gantt chart for $1-$doz $2-$oven scenario.

kcc$-1$doz$-2$ovens.png

Will the capacity double if another oven is added?

The best answer is

it will double even if everything else of the process remains the same

$.$

How much would you be willing to pay in general for renting a second oven? You don't need to give specific amount but in general what is the principle.