Question 291106
Let x = # of nickels
Therefore, 36 - x = # of dimes.

5x + 10(36 - x) = 290
5x + 360 - 10x = 290
-5x = -70
{{{highlight(x = 14)}}} nickels

36-14 = 22 dimes

Check:
0.05 * 14 = 0.70; 0.10 * 22 = $2.20, Total $2.90.  OK.