Suppose you add x liters of pure water to the 10 L of 25% acid solution. The new solution's volume is x + 10 L. Each L of pure water contributes no acid, while the starting solution contains 2.5 L of acid. So in the new solution, you end up with a concentration of (2.5 L)/(x + 10 L), and you want this concentration to be 10%. So we have

and so you would need to add 15 L of pure water to get the desired concentration of acid.
Answer:
It would be the 2nd one
Step-by-step explanation:
Answer:
x = 10.52 m
Step-by-step explanation:
Given that,
Length of a park = 90 m
Width of a park = 60 m
Area, A = 9000 m²
A uniform strip borders all four sides of the park for parking. We need to find the width of the strip. Let it is x. Now the area becomes,
(90+2x)(60+2x) = 9000

So, the width of the strip is equal to 10.52 m.
Answer:
4th option
Step-by-step explanation:
x² - 2x - 3 = 0 ( add 3 to both sides )
x² - 2x = 3
using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 1)x + 1 = 3 + 1
(x - 1)² = 4
Hi!
A perfect square is the product of when a whole number is multiplied by itself
Ex:
6 × 6 = 36, 36 is the perfect square.
The number that is being multiplied is the square root.
So to find the correct answer for this question, let's use the process of elimination.
100 = 10 × 10 so we can cross out 100
64 = 8 × 8 so we can cross out 64
25 = 5 × 5 so we can cross out 25
Now all we have left is 24, which is not a perfect square.
Answer: A. 24
Hope this helps :)