Answer:
Hi there, Welcome to brainly, I see this is your first posted question, Even though I am no expert I will try to answer your question.
Step-by-step explanation:
In order to solve this problem, you need to apply the formula y = k/x. Where y is the time it takes and x is how fast she is driving.
Substitute our given information to the formula to find k, we have : 40 = k/9. --> k = (40).9 = 360
Then do the same thing in the new number using the found k to find the time : y = 360/ 12= 30 s
It takes 30s if she rides at 12 m/h
Hope this help