Dave and Ellen are newly married and ilving in their first house. The yearly premium on their homeowner's insurance policy is $350 for the coverage they need. Their insurance comp ny offers a discount of 8 percent if they install dead-bolt locks on all exterior doors. The couple can also receive a discount of 5p cent if they install smoke detectors on each floor. They have contacted a locksmith. who will provide and install dead-bolt locks o the two exterior doors for $68 each. At the local hardware store, 5 moke detectors cost $12 each, and the new house has two floors. ave and Ellen can install the smoke detectors themselves. 0. Assuming their insurance rates remain thr ame, how many years will it take Dave and Ellen to earn back in discounts the cost of the dead-bolts? (Do not round intermediati :alculations. Round your answer to 2 decimal ploces.) b. How many years will it fake Dave and Alen to earn back in discounts the cost of the smoke detectors? (Do not round intermediote calculetions. Round your answer to 2 s cimal places.)