4. 30 is what percent of 120?

Mathematics

2 answers:

s2008m [1.1K]3 years ago

8 0

Answer:

If is 4.3

$\large\boxed{4.3\ \text{is}\ 3\dfrac{7}{12}\%\approx3.58\%\ \text{of 120}}$

If is 30

$\large\boxed{30\ \text{is}\ 25\%\ \text{of 120}}$

Step-by-step explanation:

$\bold{METHOD\ 1:}\\\\\begin{array}{ccc}120&-&100\%\\4.3&-&x\%\end{array}\qquad\text{cross multiply}\\\\\\120x=(4.3)(100)\\\\120x=430\qquad\text{divide both sides by 120}\\\\x=\dfrac{430}{120}\\\\x=\dfrac{43}{12}\\\\x=3\dfrac{7}{12}\to x\approx3.58$

$\bold{METHOD\ 2:}\\\\\text{We calculate what fraction of 120 is 4.3}\\\\\dfrac{4.3}{120}=\dfrac{4.3\cdot10}{120\cdot10}=\dfrac{43}{1200}\\\\\text{Convert to the percent:}\\\\\dfrac{43}{1200}=\dfrac{43}{1200}\cdot100\%=\dfrac{43}{12}\%=3\dfrac{7}{12}\%$

If is 30:

$\bold{METHOD\ 1:}\\\\\begin{array}{ccc}120&-&100\%\\30&-&x\%\end{array}\qquad\text{cross multiply}\\\\\\120x=(30)(100)\\\\120x=3000\qquad\text{divide both sides by 120}\\\\x=\dfrac{3000}{120}\\\\x=25$

$\bold{METHOD\ 2:}\\\\\text{We calculate what fraction of 120 is 30}\\\\\dfrac{30}{120}=\dfrac{1}{4}\\\\\text{Convert to the percent:}\\\\\dfrac{1}{4}=\dfrac{1}{4}\cdot100\%=25\%$