Question 344714
Your piggy bank has a total of 47 coins in it; some are dimes and some are nickels. If you have a total of $3.95, how many nickels and how many dimes do you have? Show all of your work to receive full credit.
I tried for at least 20 min and only got this,
:
d+n=47
:
.10d+.05n=3.95
:
n=d+47; this is wrong, it should be
n = (47-d)
so you have:
.10d+.05(47-d)=3.95
.10d + 2.35 - .05d = 3.95
.10d - .05d = 3.95 - 2.35
.05d = 1.60
d = {{{1.6/.05}}}
d = 32 dimes
then
n = 47 - 32
n = 15 nickels
:
Check this
.05(15) + .10(32) =
.75 + 3.20 = 3.95
;
You had the right idea, but a fatal mistake right at the beginning.