Answer:
$20
Step-by-step explanation:
the manager's error could likely be putting the percentage mark up rather than the markup price added to the original price
25%×16
= $4
mark up price= (16+4)$
= $20
x=6
4x-1=2x+11
4x-2x-1=11
2x-1=11
2x=11+1
2x=12
x=12/2