Alexandra has 36 coins valued at $6.00. She has only nickels and quarters. Which equation can be used to solve for the number of nickels, n?

0.05n + 0.25(36 – n) = 6
0.05n + 0.25(36 – n) = 36
n + 0.05 = 0.05n
n + (36 – n) = 36

Question

Alexandra has 36 coins valued at $6.00. She has only nickels and quarters. Which equation can be used to solve for the number of nickels, n?

0.05n + 0.25(36 – n) = 6
0.05n + 0.25(36 – n) = 36
n + 0.05 = 0.05n
n + (36 – n) = 36

Mercury · Answer

thoughts on this one?

the value of some nickels = (0.05) * (number of nickels), since each nickel is worth $0.05
similar logic with the quarters, their value would be 0.25 * (number of quarters)

now, since the equations are defined in terms of nickels (n) only, you'll also have to re-write the # of quarters in terms of the # of nickels. since there are 36 coins total, the number of quarters would be 36 - n, correct?

with all this info in mind, can you try constructing an equation to represent the total value?