Answer:
$40
Step-by-step explanation:
If he spent $40 and has none left that means he currently has $0.
If you subtract $40 - b = $0
b = $40
42
The height of the pole is 4 times shorter than the length of the shadow 20÷5=4
The height of the building must be 4 times shorter than its shadow length 168÷4=42
here
