<PRE><B>Question 249788</B>
A piggy bank contains 20 coins, consisting of nickel and dimes.
 How many of each type of coin are there if the piggy bank contains $1.40?
:
Let x = no. of dimes
then
(20-x) = no. of nickels
;
.05(20-x) + .10x = 1.40
:
1 - .05x + .10x = 1.40
:
-.05x + .10x = 1.40 - 1
:
.05x = .40
x = {{{.40/.05}}}
x = 8 dimes
and
20 - 8 = 12 nickels
:
:
Check solutions
.05(12) = .10(8) = 
.60 + .80 = 1.40</PRE>