Sonji has $5.25 in nickels and dimes. the coin value can be modeled by the equation 0.10d + 0.05n = 5.25, where d represents the number of dimes and n represents the number of nickels. if sonji has 21 dimes, how many nickels does she have?

35
42
63
105

The equation given in the question is
0.10d + 0.05n = 5.25
Putting d = 21, we get
(0.10 * 21) + 0.05n = 5.25
2.1 + 0.05n = 5.25
0.05n = 3.15
n = 63
From the above deduction, it can be easily concluded that the correct option among all the options that are given in the question is the third option or the penultimate option. I hope that the answer has actually come to your great help.