The word "times" means you have to multiply.
2 1/5 times 1 3/4 is 3 17/20.
The phrase "how many more" means you have to subtract.
3 17/20 minus 2 1/5 is 1 13/20.
Carson walked her dog 1 13/20 more miles than Claire did.
Sorry for the lazy explanations Imao