<PRE><B>Question 4279</B>
Let x = number of nickels 
 51 - x = number of dimes


Value of coins = number of coins times value of each coin (in cents)
Value of nickels + Value of dimes = Total value of coins ($3.80 or 380 cents)
5(x)   +    10(51 - x) = 380
5x + 510 - 10x = 380
-5x + 510 = 380
-5x + 510 - 510 = 380 - 510
-5x = -130
x=26 Nickels
51 - x = 25 Dimes


Check:  
Total value of nickels = $1.30
Total value of dimes   = $2.50
Total value of coins   = $3.80 </PRE>