MCQ
$0.14189189189….$ can be expressed as a rational number
  • A
    $\frac{7}{{3700}}$
  • B
    $\frac{7}{{50}}$
  • C
    $\frac{{525}}{{111}}$
  • $\frac{{21}}{{148}}$

Answer

Correct option: D.
$\frac{{21}}{{148}}$
d
(d) $0.14189189189....$

$ = 0.14 + 0.00189 + 0.00000189 + .......$

$ = \frac{{14}}{{100}} + 189\left[ {\frac{1}{{{{10}^5}}} + \frac{1}{{{{10}^8}}} + ....\infty } \right]$

$ = \frac{7}{{50}} + 189\,\left[ {\frac{{1/{{10}^5}}}{{1 - (1/{{10}^3})}}} \right]$$ = \frac{7}{{50}} + 189\,\left[ {\frac{1}{{{{10}^5}}} \times \frac{{{{10}^3}}}{{999}}} \right]$

$ = \frac{7}{{50}} + \frac{{189}}{{999 \times 100}}$

$ = \frac{7}{{50}} + \frac{7}{{3700}} = \frac{7}{{50}} + \frac{7}{{25 \times 148}}$$ = \frac{{21}}{{148}}$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free