Question

Simplify
$(1.5+\frac{3}{8})^3-(\frac{9}{5}\times 1.25)$

• A. 4.3418
• B. 5.3418
• C. 6.5526
• D. 7.5526

Answer 1

Answer:

A. 4.3418

Simplify step by step:

$\left(1.5+\frac{3}{8}\right)^3-\left(\frac{9}{5}\times1.25\right)$

Convert decimals to fractions:

$1.5=\frac{3}{2},\qquad 1.25=\frac{5}{4}$

So,

$\left(\frac{3}{2}+\frac{3}{8}\right)^3-\left(\frac{9}{5}\times\frac{5}{4}\right)$

Add the fractions:

$\frac{3}{2}=\frac{12}{8}$

$\frac{12}{8}+\frac{3}{8}=\frac{15}{8}$

Cube it:

$\left(\frac{15}{8}\right)^3=\frac{15^3}{8^3}=\frac{3375}{512}$

Multiply the second term:

$\frac{9}{5}\times\frac{5}{4}=\frac{9}{4}$

Subtract:

$\frac{3375}{512}-\frac{9}{4}$

$=\frac{3375}{512}-\frac{1152}{512}=4.3418$