Answer:
The worth of one bill is $20 and the worth of the other bill is $1
Step-by-step explanation:
Let
x----> the worth of one bill
y ---> the worth of the other bill
I assume x > y
we know that
x+y=21 ----> equation A
x=y+19 ---> equation B
Solve the system by elimination
Multiply equation B by -1 both sides
-x=-y-19 ----> equation C
Adds equation A and equation C
x+y=21
-x=-y-19
------------
y=21-y-19
2y=2
y=1
Find the value of x
x=y+19 -----> x=1+19=20
therefore
The worth of one bill is $20 and the worth of the other bill is $1