martas math textbook weighs $\frac{4}{5}$ of a pound less than 4 times the weight of the book she is reading…

martas math textbook weighs $\frac{4}{5}$ of a pound less than 4 times the weight of the book she is reading for her language arts class. if the weight of the math textbook is $2\frac{1}{5}$ pounds, which shows the correct equation and value of $x$, the weight of martas book for language arts?\n$4x + \frac{4}{5}=2\frac{1}{5};x = \frac{7}{20}$ of a pound\n$4x-\frac{4}{5}=2\frac{1}{5};x=\frac{3}{4}$ of a pound\n$4x+\frac{4}{5}=2\frac{1}{5};x=\frac{3}{4}$ of a pound\n$4x - \frac{4}{5}=2\frac{1}{5};x=\frac{7}{20}$ of a pound
Answer
Explanation:
Step1: Translate the problem into an equation
Let $x$ be the weight of the language - arts book. The math textbook weighs $\frac{4}{5}$ of a pound less than 4 times the weight of the language - arts book. So the equation is $4x-\frac{4}{5}=2\frac{1}{5}$.
Step2: Convert the mixed - number to an improper fraction
$2\frac{1}{5}=\frac{2\times5 + 1}{5}=\frac{11}{5}$. The equation becomes $4x-\frac{4}{5}=\frac{11}{5}$.
Step3: Add $\frac{4}{5}$ to both sides of the equation
$4x=\frac{11}{5}+\frac{4}{5}$. Since $\frac{11}{5}+\frac{4}{5}=\frac{11 + 4}{5}=\frac{15}{5}=3$, we have $4x = 3$.
Step4: Solve for $x$
Divide both sides of the equation $4x = 3$ by 4, so $x=\frac{3}{4}$.
Answer:
B. $4x-\frac{4}{5}=2\frac{1}{5};x = \frac{3}{4}$ of a pound