Question 1099158
We will want an equation for the NUMBER of coins. d+n=65
We will also want an equation for the VALUE of coins. .10d+.05n=5.35
.10d+.05n=5.35
d+n=65
Let's get rid of decimals.
10d+5n=535
d+n=65
multiply by 5

5d+5n=65*5
10d+5n=535
5d+5n=325
subtract
5d=535-325=210
d=210/5=42
d+n=65
42+n=65
n=23
check
10d+5n=535
10*42+5*23=535
ok