Question

A chemist wants to mix a 70% saline solution with a 8 liters of a 25% saline solution to create a solution with 40% salt. How many liters of the 70% solution does she need.

Answer 1

Answer:

The quantity of 70% saline solution chemist need is 4 liters

Step-by-step explanation:

Given as :

The quantity of 25% saline solution = 8 liters

Let The quantity of 70% saline solution chemist need = x liters

The quantity of 40% saline solution mixture = (x+8) liters

Now, According to question

∵The mixture is created with solutions

So, 25% of quantity of saline + 70% of quantity of saline = 40% of quantity of mixture

Or, 25% of 8 liters + 70% of x liters = 40% of (x+8) liters

Or, $\dfrac{25}{100}$ × 8 + $\dfrac{70}{100}$ × x =  $\dfrac{40}{100}$ × (x+8)

Or, $\frac{25\times 8}{100}$ + $\frac{70\times x}{100}$ = $\frac{40\times (x +8)}{100}$

Or, 200 + 70 x = 40 × (x+8)

Or, 200 + 70 x = 40 x + 320

Or, 70 x - 40 x = 320 - 200

Or, 30 x = 120

∴  x = $\dfrac{120}{30}$

i.e x = 4 liters

So,The quantity of 70% saline solution chemist need = x = 4 liters

Hence, The quantity of 70% saline solution chemist need is 4 liters Answer