21. A selection of jigsaw puzzles at one store is priced at $12 each. During a sale, a customer who buys 2 of these puzzles at the regular price may buy
additional puzzles at half price. How many puzzles could a customer buy
for $42?

Technicians have installed a center pivot, circular irrigator for a farm that covers 25 acres. a.) how long is the irrigation boom (in feet) from the center pivot to its farthest extent? b.) if the irrigation boom makes 4 full revolutions in a day, how many miles does the end of the boom travel in 5 days?