Question 186830
n + d = 6.05.........  Equation A
(n - 10) + 2d = 9.85...Equation B

Solve for n in Equation A.

n = 6.05 - d

We plug that value for n into Equation B.

6.05 - d + 2d = 9.85

6.05 + d = 9.85

d = 9.85 - 6.05

d = 3.80....This is the total value of the dimes Joe has.  However and as you know, each dime is 10 cents.

How many dimes are in $3.80?  There are 38 dimes.

To find the value of n, we select EITHER Equation A or B, plug 3.80 for d and simplify to find n.  If you look carefully, you will notice that Equation A is easier to use.

I will use Equation A.

n + d = 6.05...Equation A

n + 3.80 = 6.05

n = 6.05 - 3.80

n = 2.25

How many nickels in $2.25? 

Joe has 45 nickels.