if d = number of dimes, then number of nickels n = d - 5

so if n = d - 5, you can sub "d - 5" for n in the second equation:

5n + 10d = 5540 (5n because nickels are 5 cents each, 10d because dimes are 10 cents each, and 5540 is $55.40 in cents--let's do it all in cents for now...)

anyway, because of the substitution, we can say that:

5 (d - 5) + 10d = 554o, so

5d - 25 + 10d = 5540, so

15d = 5565, so

d = **371 dimes.** 371 dimes equals 3710 cents. Subtract that from 5540 cents to get 1830 worth of nickels.

1830 divided by 5 = **366 nickels**

Hope this helps!

Matt in NY