Can somebody help me on this

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document

If its non of them tell me..valerie took a day-trip. she drove from her house for a while and took a coffee break. after her coffee break, she continued driving. after  2  hours of driving after her coffee break, her distance from her house was  210  miles. her average speed during the whole trip was  60  miles per hour.valerie created the equation  y−210=60(x−2)  to represent this situation, where  xx  represents the time in hours from her coffee break and  yy  represents the distance in miles from her house.which graph correctly represents valerie's distance from her house after her coffee break?

Aculinary club earns $1360 from a dinner service. they sold 45 adult meals and 80 student meals. an adult meal costs twice as much as a student meal. what is the cost of an adult meal?