Deirdre Bought a Secondhand Car from Honest Harry's Autos After

Deirdre bought a secondhand car from Honest Harry's Autos after being assured by Harry, in response to her questions, that the car had been driven only in good weather by the little old lady from whom he had purchased it. He claimed that was why its mileage was so low, and that it had never, (according to the little old lady), had so much as a scratch. "That's excellent," said Deirdre. "If it had been otherwise, I wouldn't have bought it."
Deirdre soon began having trouble with the car pulling to one side when she applied the brakes, so she took it into the garage for a wheel alignment. The mechanic said "Why on earth would you buy this old heap? Granny Moses, that wild old lady, drove this thing like a madwoman, and it's never been the same since her last crash."
a. Assuming that Honest Harry had also been fooled by Grandma Moses, what rights would he and Deirdre each have?
b. Suppose Honest Harry found out after he sold the car to Deirdre that he had been cheated by Grandma Moses, but decided not to tell Deirdre. How would that affect Deirdre's rights and why?