It takes 1 hour for 1 worker to clean an area that is 20 feet by 30 feet. How many workers are needed to clean 18,400 square feet in 8 hours?

4 workers

Step-by-step explanation:

20 ft x 30 ft = 600 sq ft per worker per hour x 8 hours = 4800 sq ft per worker

18,400 sq ft divided by 4800 = 3.83 so 4 workers

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!