If you're asking the difference between 14 ft and 21 ft your answer is 7 ft, just subtract 14 from 21
Answer: $0.3
Step-by-step explanation:
Given
The owner buys 144 pens for $28.80 i.e. each pen costs

owner sells the pen at $0.4 i.e. price marked up by

So, the claim of the owner is incorrect
The actual increase in the price to get 50% markup

Multiply by 0.4 on both sides to cancel the original 0.4 and change the 10
Answer:
A. $2.25
Step-by-step explanation:
If you subtract $7.50 from $18.75 you get $11.25, then divide that by 5 and you'll get $2.25.
Hope this was useful.