Respuesta :

Given:

1/5 of Barry's salary was going for his rent.

1/7 of Barry's salary was going for his utility bill.

1012 dollars was left after all the payments.

Required:

What was his monthly salary?

Explanation:

Let us assume that Barry's monthly salary is 'x'

So the sum of his payments and the balance amount will give us his total salary.

[tex]total\text{ }salary=rent\text{ }payment+utility\text{ }payment+money\text{ }left[/tex]

Now Barry uses 1/5 of his salary in rent, that is

[tex]\begin{gathered} rent\text{ }payment=\frac{1}{5}\times his\text{ }total\text{ }salary \\ \\ rent\text{ }payment=\frac{1}{5}\times x \end{gathered}[/tex]

Barry uses 1/7 of his salary in utility bill, that is

[tex]\begin{gathered} utility\text{ }bill=\frac{1}{7}\times his\text{ }total\text{ }salary \\ \\ utility\text{ }bill=\frac{1}{7}\times x \end{gathered}[/tex]

And after all the payments the money he is left with is 1012 dollars.

[tex]money\text{ }left=1012[/tex]

Now let's calculate his total salary

[tex]\begin{gathered} total\text{ }salary=rent\text{ }payment+utility\text{ }bill+money\text{ }left \\ \\ x=\frac{1}{5}\times x+\frac{1}{7}\times x+1012 \\ \\ x=\frac{x}{5}+\frac{x}{7}+1012 \\ \\ x=\frac{7x+5x}{35}+1012 \end{gathered}[/tex]

Simplifying it further we get

[tex]\begin{gathered} x=\frac{12x}{35}+1012 \\ \\ x-\frac{12x}{35}=1012 \\ \\ \frac{35x-12x}{35}=1012 \\ \\ \frac{23x}{35}=1012 \end{gathered}[/tex][tex]\begin{gathered} 23x=1012\times35 \\ \\ 23x=35420 \\ \\ x=\frac{35420}{23} \\ \\ x=1540 \end{gathered}[/tex]

x = 1540 dollars

Final Answer:

Barry's monthly salary is 1540 dollars.