8 litres (amount of 20% solution needed) and 7 litres for (amount of 50% solution needed)
<u>Step-by-step explanation:</u>
Let consider ‘x’ for 20% acid solution and (15 – x) for 50% acid solution. And so, the equation would be as below,
20% in x + 50% in (15 – x) = 15 litres of 34%
Convert percentage values, we get
0.20(x) + 0.50 (15 – x) = 15 (0.34)
0.20 x + 7.5 – 0.50 x = 5.1
-0.3 x + 7.5 = 5.1
0.3 x = 7.5 – 5.1
0.3 x = 2.4

Apply ‘x = 8’ value in (15 – x) we get,
15 – 8 = 7 litres
The value of 7 litres for (amount of 50% solution needed)
The equation which shows the associative property of addition is; (–7 + i) +7i = –7 (i +7i).
<h3>What is the associative property of addition?</h3>
Associative property of addition postulates that Changing the grouping of addends does not change the sum of the numbers. As an instance, ( 5 + 3 ) + 4 = 5 + ( 3 + 4 )
Consequently, the equation which shows the associative property of addition is; (–7 + i) +7i = –7 (i +7i)
Read more on associative property of addition;
brainly.com/question/2284106
#SPJ1
Answer:
12:1
………………………………………………
brainiliest me then i can follow you pleasee