3more than a number t is greater than or equal to 21

If the measure of xyz is 81 what is the measure of yz

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?

Ahealth-food producer has 250 samples of a new snack to distribute in the mall. the producer has to keep at least 50 samples for display in the health food for the product launch. how long will the samples last if consumers are taking the samples at a rate of 25 every hour