Answer:
<em>Rajan must use </em><em>0.75</em><em> liters of 5% hydrochloric acid solution and </em><em>0.25</em><em> liters of 45% hydrochloric acid solution.</em>
Step-by-step explanation:
Let us assume that, x liters of the 5% hydrochloric acid and y liters of the 45% hydrochloric acid solutions are combined.
As Rajan need total of 1 liter of solution, so
i.e
--------------------1
As Rajan needs 5% hydrochloric acid and 45% hydrochloric acid to make a 1 liter batch of 15% hydrochloric acid, hence acid content of the mixture of two acids will be same as of the final one, so

i.e
-------------2
Putting value of x from equation 1 in equation 2,





Putting the value of y in equation 1,

Therefore, Rajan must use 0.75 liters of 5% hydrochloric acid solution and 0.25 liters of 45% hydrochloric acid solution.
Answer:
no
Step-by-step explanation:
A proportional relationship must go through (0,0)
c=7n+2
0 = 7(0) +2
0 = 2
This is not true so it is not a proportional relationship
Answer: it's impossible to obtain 78
Step-by-step explanation: Since the calculator can double any number or permute its digits except 0
starting with number 1
1, 2, 4, 8, 16, 32, 64, 128
Therefore, it's impossible to obtain 78 by a series of these operations