Okay, so there are nickels and pennies in this jar.
So, let's call the number of pennies X
Since there are 161 coins altogether, the number of nickels is (161 - X)
So now we solve the equation:
.01X + .05(161 - X) = 3.09
.01X + 8.05 - .05X = 3. 09
4.96 = .04X
124 = X
So, there are 124 pennies
Therefore, there are 161 - 124 = 37 nickels
Let's check our answer:
124 x .01 + 37x .05 = 1.24 + 1.85 = 3.09
It works!