Bryan has quarters and nickels in his piggy bank. He has three times as many nickels as he has quarters. If the total value of the coins is $12, find the number of nickels in the piggy bank.

90

Step-by-step explanation:

Quarters , q = 25 cent

Nickel, n = 5 cent

3 times as many nickels as quarters;

n = 3q

Total value of coins = $12

n + q = $12

0.05n + 0.25q = 12

0.05(3q) + 0.25q = 12

0.15q + 0.25q = 12

0.40q = 12

q = 12 / 0.40

q = 30

n = 3q

n = 3(30)

n = 90

90 nickels

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!