He has 10 pennies, 13 quarters , 21 dimes and 25 nickels.
Step-by-step explanation
Suppose, the number of pennies is
![x](https://img.qammunity.org/2019/formulas/mathematics/college/lhtxftojjkzsmo3o2h4ilq8naohracejui.png)
As he has 3 more quarters than pennies, 11 more dimes than pennies and 2.5 times as many nickels as pennies....
So, the number of quarters
,
the number of dimes
and
the number of nickels
![=2.5x](https://img.qammunity.org/2019/formulas/mathematics/middle-school/wtbtey7daelq21j0u9u8npvpwiduxjxft3.png)
We know, the value of each penny is $0.01 , value of each quarter is $0.25 , value of each dime is $0.10 and value of each nickel is $0.05
Given that, the total value of all coins is $6.70
So the equation will be.....
![0.01x+0.25(x+3)+0.10(x+11)+0.05(2.5x)=6.70\\ \\ 0.01x+0.25x+0.75+0.10x+1.10+0.125x=6.70\\ \\ 0.485x+1.85=6.70\\ \\ 0.485x=6.70-1.85=4.85\\ \\ x=(4.85)/(0.485)=10](https://img.qammunity.org/2019/formulas/mathematics/middle-school/r32liqt4o5jaz0ldzbs3accmwq8mrg0j65.png)
So, the number of pennies is 10 , number of quarters is (10+3)= 13 , number of dimes is (10+11)= 21 and number of nickels is (2.5×10)= 25