Help please !
What is the range ?

Phoebe runs a t-shirt printing business. she ships the t-shirts to retailers in boxes of 200. she has two automated printing machines that can print designs on t-shirts. one machine can print 200 t-shirts in 50 minutes. the other machine can print 200 t-shirts in 150 minutes. if the two machines work at the same time, they can print 200 t-shirts in ….. minutes.