Answer:
Step-by-step explanation:
First, turn the word problem into an equation:
n(a number) was divided by 2

followed by this quotient beying multiplied by 4
*4
the product was added to 9
*4+9
the total sum was 25
*4+9 = 25
use PEMDAS to solve the equation
subtract 9 on both sides
*4 = 16
cancel the 2 and the 4 using factorization
n*2 = 16
divide 2 on both sides
n = 8
X liters of 10% + (30 - x) liters of 22% = 30 liters of 15%
<span>Plugging in the numbers </span>
<span>x(10) + (30 - x)22 = 30(15) </span>
<span>Distribute </span>
<span>10x + 660 - 22x = 450 </span>
<span>Combine like terms </span>
<span>-12x = -210 </span>
<span>Divide both sides by -12 </span>
<span>x = 17.5 </span>
<span>30 - x = 12.5 </span>
<span>17.5 liters of 10% + 12.5 liters of 22% = 30 liters of 15%
THE TRICK IS TO JUST USE ONLY ONE VARIABLE</span>