Let the number of dimes be x
Then the number of nickels, using
ONE PART = TOTAL MINUS OTHER PART,
is 52-x.
Value Value
Type Number of of
of of EACH ALL
coin coins coin coins
-------------------------------------------
dimes x $0.10 $0.10x
nickels 52-x $0.05 $0.05(52-x)
-------------------------------------------
TOTALS 52 ----- $3.55
The equation comes from the column on the right
0.10x + 0.05(52-x) = 3.55
Get rid of decimals by multiplying every term by 100:
10x + 5(52-x) = 355
10x + 260 - 5x = 355
5x + 260 = 355
5x = 95
x = 19 = the number of dimes.
The number of nickels is 52-x or 52-19 or 33 nickels.
Checking: 19 dimes is $1.90 and 33 nickels is $1.65
That's 52 coins.
And indeed $1.90 + $1.65 = $3.55
Edwin