D.FIRST CALCULATE THE NUMBER OF LETTERS COMPLETED BY 30 TYPISTS IN...

8. d.First calculate the number of letters completed by 30 typists in 20 minutes. Let x= the number of

typists

letters typed by 30 typists and set up the proportion . Cross-multiply to get

letters

²⁰

48

³⁰

x

20x= 1,440. Divide both sides by 20 and get x= 72. Since 20 minutes is one-third of an hour, multiply72 ×3 = 216 to get the total letters for one hour.