Question 1169800
<br>
Let x be the number of 20c coins.<br>
Then 2x is the number of $1 coins (twice as many as 20 cent coins).<br>
Then 36-3x is the number of 50c coins (the total number of coins is 36).<br>
The value of the 50c coins is $4.40 more than the value of the 20c coins:<br>
{{{50(36-3x) = 20(x)+440}}}
{{{1800-150x = 20x+440}}}
{{{1360 = 170x}}}
{{{x = 8}}}<br>
ANSWER: The number of $1 coins is 2x = 16.<br>
The solution can be found much more quickly informally using logical reasoning and a bit of simple arithmetic.<br>
For the difference between the value of the 50c coins and the 20c coins to be $4.40, the value of the 50c coins must be a whole dollar amount and the number of 20c coins must be 3, or 8, or 13, or....<br>
Now do some quick trial and error arithmetic:<br>
3 20c coins (value $0.60) means 10 50c coins (value $5.00); 3 20c coins means 2*3=6 $1 coins.  The total number of coins is 3+10+6 = 19.  Not right....<br>
8 20c coins (value $1.60) means 12 50c coins (value $6.00); 8 20c coins means 2*8=16 $1 coins.  The total number of coins is 8+12+16 = 36. CORRECT!<br>
ANSWER: 16 $1 coins<br>