Let the number of nickels be x
Then the number of quarters, using
ONE PART = TOTAL MINUS OTHER PART,
is 11-x.
Value Value
Type Number of of
of of EACH ALL
coin coins coin coins
-------------------------------------------
nickels x $0.05 $0.05x
quarters 11-x $0.25 $0.25(11-x)
-------------------------------------------
TOTALS 11 ----- $1.35
The equation comes from the column on the right
0.05x + 0.25(11-x) = 1.35
Get rid of decimals by multiplying every term by 100:
5x + 25(11-x) = 135
5x + 275 - 25x = 135
-20x + 275 = 135
-20x = -140
x = 7 = the number of nickels.
The number of quarters is 11-x or 11-7 or 4 quarters.
Checking: 7 nickels is $0.35 and 4 quarters is $1.00
And indeed $0.35 + $1.00 = $1.35
Edwin