Question

Your piggy bank has a total of 18 coins in it; some are dimes and some are nickels. If you have a total of $1.40, how many nickels do you have?

14

12

10

8

Answer 1

1.4=.1x+.05y

Answer 2

10 dimes 8 nickels

Answer 3

Let x=number of nickels. Since there are 18 coins total, then 18-x=number of dimes. Since we know the total value is 140 cents, then 5 times the number of nickels plus 10 times the number of dimes equals 140.
\[5x+10(18-x)=140\] Distribute and simplify:
\[5x+180-10x=140\]
\[-5x=-40\]
\[x=\]

Answer 4

I got a decimal

Answer 5

I don't know why this didn't post:
\[x=-40/-5=8 nickels\]

Answer 6

okay thank you!