there are four $5 bill and twenty one $10 bill in your wallet
Step-by-step explanation:
1) defining the variables
let the number of $5 bill = x
Let the number of $10 bill = y
2) Total bills = 25
x + y = 25
The sum of the total bills = $230
5× x + 10 ×y = 230
5x + 10y = 230
The system of equation:
x + y = 25 ....equation 1
5x + 10y = 230 ...equation 2
3) solving the system:
x + y = 25 ....equation 1
5x + 10y = 230 ...equation 2
using elimination method:
we need to ensure the variable we want to eliminate have same coefficient in both equations.
Let's eliminate 5: multiply equation 1 by 5
5x + 5y = 125 ....equation 1
5x + 10y = 230 ...equation 2
subtract equation 1 from 2:
5x - 5x + 10y - 5y = 230 - 125
0 + 5y = 105
5y = 105
5y/5 = 105/5
y = 21
Substitute 21 for y in any of the equation. Using equation 1:
5x + 5(21) = 125
5x + 105 = 125
5x = 125 - 105
5x = 20
5x/5 = 20/5
x = 4
Hence, there are four $5 bill and twenty one $10 bill in your wallet