Answer: dvd= $8.40 book= $1.60
Step-by-step explanation:
So we know the equations for each would be
Anna
d+6b=18
David
4d+4b=40
Let's find for d first using Anna since she bought only 1 DVD...
d+6b=18
d=18-6b
Plug that in...
4(18-6b)+4b=40
72-24b+4b=40
72-20b=40
72-40=20b
32=20b
1.6=b
Plug that in to find d...
d=18-6(1.6)
d=18-9.6
d=8.4
