Question

A purse contains 21 coins consisting of nickels and dimes. Find the number of coins of each kind if the total value is $1.65.

If 5n represents the value of the nickels, then which of the following expressions represents the value of the dimes?

A.10n
B.16n
C.10(21 - n)

Answer 1

nickles + dimes = 21 coins
n + d = 21 (eq 1)
let n be the number of nickels
let d be the number of dimes

0.05*n + 0.10*d= 1.65 (eq 2)

2 equations, 2 unknowns, so, substitute equation (1) into equation (2)

solve for either n or d with the new eqation made

Answer 2

I wrote a Python script and spun through the possibilities: 9 nickels, 12 dimes.

Answer 3

*intresting...