Please show step by step. I missed this one

1. A grocery chain is considering the installation of a set of 4 self-checkout lanes. The new self-checkout lane setup will replace 2 old cashier lanes that were staffed by a cashier and bagger on each lane per shift. One cashier alone covers all 4 self-checkouts per shift (answering questions, checking for un-scanned items, taking coupons, etc). A checkout on the new lanes takes 1.8 minutes (customers bag their own orders) while checkout with the old lanes took only 50 seconds. In addition, the electricity costs for both setups are $0.04 per checkout while bagging (material) costs are $0.15 per checkout with the old system and $0.20 for the new system. The new 4 self-checkout lanes also require $25/shift/lane in capital costs (new computer system). Assume that the lanes are always in use for 16 hours per day (2 shift/day), the average revenue per checkout is $11, and that a worker (cashier and bagger) makes $11/hour.

1. How many checkouts could the old system provide per shift?
2. How many checkouts does the new system provide per shift?
3. What is the unit-less multifactor productivity for each system (old or new)?
4. Which checkout system is more productive and what is the percent change in productivity for the new system relative to the old system ((new-old)/old*100)?