Saved Help Save & Exit Submit Check my work Dave and Ellen are newly married and living in their first house. The yearly premium on s insurance policy is $800 for the coverage they need. Their insurance company offers a discount of 7 percent if they install dead-bolt locks on all exterior doors. The couple can also receive a discount of 4 percent if t ' ey install smoke detectors on each floor. They have contacted a locksmith, who will provide and install dead-bolt locks on the two exterior doors for $120 each. At the local hardware store, smoke detectors cost $30 each, and the new house has two floors. Da 'e and Ellen can install them themselves. Dave and a. Assuming their insurance rates remain the same, how many years will it take Ellen to earn back in discounts the cost of the dead-bolts? (Round your answer to 2 decimal places.) ur 0 period years lic b. How many years will it take Dave and Ellen to earn back in discounts the cost of the smoke detectors? (Round your answer to 2 decimal places.) er elon 551 the Recovery period years ceive yme the Prev7 of 13 Next>