if 3/4 of a number is added to 5/4 it gives the same result as taking 7/8 of the number from 20 ⅓. Find the number​

Sagot :

Given:

[tex]\dfrac{3}{4}[/tex] of a number is added to [tex]\dfrac{5}{4}[/tex] it gives the same result as taking [tex]\dfrac{7}{8}[/tex] of the number from [tex]20\dfrac{1}{3}[/tex].

To find:

The unknown number.

Solution:

Let x be the unknown number.

[tex]\dfrac{3}{4}[/tex] of a number is added to [tex]\dfrac{5}{4}[/tex] it gives the same result as taking [tex]\dfrac{7}{8}[/tex] of the number from [tex]20\dfrac{1}{3}[/tex].

[tex]\dfrac{5}{4}+\dfrac{3}{4}x=20\dfrac{1}{3}-\dfrac{7}{8}x[/tex]

[tex]\dfrac{5+3x}{4}=\dfrac{61}{3}-\dfrac{7}{8}x[/tex]

[tex]\dfrac{5+3x}{4}=\dfrac{488-21x}{24}[/tex]

Multiply both sides by 24.

[tex]6(5+3x)=488-21x[/tex]

[tex]30+18x=488-21x[/tex]

[tex]18x+21x=488-30[/tex]

[tex]39x=458[/tex]

Divide both sides by 39.

[tex]x=\dfrac{458}{39}[/tex]

Therefore, the required number is [tex]\dfrac{458}{39}[/tex].