The ratio of the number of Mays necklaces to the number of Helen's necklace is 25:9. May has 100 necklaces. How many necklaces does Helen have.

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?