Test Index

Equations

Question : 18 of 39

Marks: +1, -0

\;\frac{5}{7}

\;\frac{4}{15}

\;\frac{2}{5}

\;\frac{4}{9}

of the same number. What is half of that number?

Solution:

Concept:

Translate the word problem into an equation and solve for the number, then find half.

Explanation:

Let the number be

x

\frac{5}{7}\times\frac{4}{15}

x

8

more than

\frac{2}{5}\times\frac{4}{9}

x

Equation:

\left(\frac{5}{7}\times\frac{4}{15}\right)x = \left(\frac{2}{5}\times\frac{4}{9}\right)x + 8

Simplify:

\frac{4}{21}x = \frac{8}{45}x + 8

Subtract

\frac{8}{45}x

\left(\frac{4}{21} - \frac{8}{45}\right)x = 8

Common denominator

315

\frac{60-56}{315}x = 8 \Rightarrow \frac{4}{315}x = 8

Multiply both sides by

\frac{315}{4}

x = 8 \times \frac{315}{4} = 2 \times 315 = 630

Half of

630

\frac{630}{2} = 315

Answer:

Half of the number is

315

, which is not among options A, B, or C.

Therefore, the correct option is D (None).

Go to Question:

Prev Question

Next Question