In a certain year, the price of gasoline rose by 20% during January, fell by 20% during February, rose by 25% in March, and fell by x % in April. The price of gasoline at the end of April was the same as it had been at the beginning of January. Find the value of x.

Respuesta :

Using decimal multipliers, it is found that the value of x is of 16.67.

What is a decimal multiplier?

Increases of a% or decreases of a% re represented by decimal values, as follows:

  • The equivalent multiplier for an increase of a% is given by: [tex]\frac{100 + a}{100}[/tex]
  • The equivalent multiplier for an decrease of a% is given by: [tex]\frac{100 - a}{100}[/tex]

In this problem:

  • The price at the beginning of January was of a.
  • Increase of 20% in January, hence [tex]1.2a[/tex].
  • Decrease of 20% in February, hence [tex]1.2(0.8)a[/tex].
  • Increase of 25% in March, hence [tex]1.2(0.8)(1.25)a[/tex].
  • Decrease of x% in April, hence [tex]1.2(0.8)(1.25)\left(\frac{100 - x}{100}\right)a[/tex]

The price of gasoline at the end of April was the same as it had been at the beginning of January, hence:

[tex]a =1.2(0.8)(1.25)\left(\frac{100 - x}{100}\right)a[/tex]

[tex]1.2\left(\frac{100 - x}{100}\right) = 1[/tex]

[tex]\left(\frac{100 - x}{100}\right) = \frac{1}{1.2}[/tex]

[tex]\frac{100 - x}{100} = 0.8333[/tex]

[tex]100 - x = 83.33[/tex]

[tex]x = 16.67[/tex]

The value of x is of 16.67.

To learn more about decimal multipliers, you can take a look at https://brainly.com/question/24952336