Exactly 80 liters of 20% are needed.
Let quantity of 20% alcohol solution be added : x liters
Here is the work:
> x*20% + 40 * 50% = (x+40) * 30%
> x*0.2 + 40*0.5 = (x+40)*0.3 ..(converting percentages into decimal)
> 0.2x + 20 = 0.3x + 12
> 20-12 = 0.3x - 0.2x (Rearranging similar terms)
> 8 = 0.1 x
Hence x = 8/0.1
Ans 80 Litres
Answer:
A veterinarian requires the most education out of the four.
Answer:
Explanation:
If John needs to ensure a 40% profit, John needs to sell the pines at a price that would give 40% more money back than he spent.
Since John needs to make back all of the money he spent, plus another 40%, John needs to get back 140% of what he spent.

John spent $3500.
140% of $3500 is $4900.
So, John must bring in $4900 (revenue) selling all 15 pines to achieve a 40% profit.
However, the question asks for the price of a single pine. To find the unit price of a single pine, divide the total revenue by 15.

I think it is the first answer choice " to explain why the Amazon Rainforest should be protected." Because that's what the passage is about. Someone explaining why the Rainforest should be protected and what will happen if it is destroyed.