David has 50 bills in his wallet worth $400 all fives and tens dollar bills. How many of each bill does he have
f + t = 50
5f + 10 t + 400
Multiply the first equation by -5 and add to the second equation.
You will find t and then find f by substituting your answer into the first equation.
To solve this problem, we can set up a system of equations based on the given information.
Let's assume the number of five-dollar bills is represented by 'x' and the number of ten-dollar bills by 'y'.
From the given information, we can create two equations:
1. x + y = 50 (since he has a total of 50 bills)
2. 5x + 10y = 400 (since the total value of the bills is $400)
We now have a system of two equations with two variables. We can solve this system to find the values of 'x' and 'y'.
From equation 1, we have x = 50 - y.
Substituting this into equation 2, we can solve for 'y':
5(50 - y) + 10y = 400
250 - 5y + 10y = 400
5y = 400 - 250
5y = 150
y = 150 / 5
y = 30
Now we know that David has 30 ten-dollar bills.
To find the number of five-dollar bills (x), we can substitute the value of 'y' back into equation 1:
x + 30 = 50
x = 50 - 30
x = 20
Therefore, David has 20 five-dollar bills and 30 ten-dollar bills in his wallet.