Answer:
11 pennies
33 nickels
7 quarters
Step-by-step explanation:
Let x be the number of pennies, then the number of nickels is 3x.
There are 51 coins in total, so the number of quarters is 51 - x - 3x = 51 - 4x.
Amounts:
Tota amount = $3.51 = 351 cents.
Hence,
[tex]x+15x+25(51-4x)=351\\ \\x+15x+1,275-100x=351\\ \\x+15x-100x=351-1,275\\ \\-84x=-924\\ \\84x=924\\ \\ x=11[/tex]
11 pennies
33 nickels
7 quarters