Carolyn eats 5 cupcakes in 20 minutes. Matt ears 6 cupcakes in 22 minutes. Who eats cupcakes faster?

Explanation:

5 cupcakes : 20 min

5/5 cupcakes : 20/5 min

1 cupcake : 4 min

Carolyn eats 1 cupcake every 4 minutes

6 cupcakes : 22 min

6/6 cupcakes : 22/6 min

1 cupcake : 3.67 min

Matt eats 1 cupcake every 3.67 minutes (roughly).

Matt is the faster eater since his time value per cupcake is smaller.

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!