Question

Find:

$\frac{1}{5^2}+\frac{1}{5^3}+\frac{1}{5^4}=$

• A. 0.496
• B. 0.0469
• C. 0.0272
• D. 0.0496

Answer 1

Answer:

D. 0.0496

$\frac{1}{5^2}+\frac{1}{5^3}+\frac{1}{5^4}$

$=\frac{1}{25}+\frac{1}{125}+\frac{1}{625}$

$=\frac{4\times1}{25\times4}+\frac{1\times8}{125\times8}+\frac{1\times16}{625\times16}$

$=\frac{4}{100}+\frac{8}{1000}+\frac{16}{10000}$

$=0.04+0.008+0.0016$

$=0.0496$