Let the number of nickels be \( n \) and the number of pennies be \( p \).
We can set up two equations based on the information given:
-
The total number of coins: \[ n + p = 21 \]
-
The total value of the coins in cents: \[ 5n + p = 77 \] (since each nickel is worth 5 cents and each penny is worth 1 cent).
Now, we can solve this system of equations.
First, we can express \( p \) from the first equation: \[ p = 21 - n \]
Next, we can substitute this expression into the second equation: \[ 5n + (21 - n) = 77 \]
Now, simplify the equation: \[ 5n + 21 - n = 77 \] \[ 4n + 21 = 77 \]
Subtract 21 from both sides: \[ 4n = 56 \]
Now, divide by 4: \[ n = 14 \]
Now, substitute \( n \) back into the equation for \( p \): \[ p = 21 - n = 21 - 14 = 7 \]
So, Rupert has:
- \( n = 14 \) nickels
- \( p = 7 \) pennies
In conclusion, Rupert has 14 nickels and 7 pennies.