Question

In scientific notation, Find $3\times {10}^{-5}+4\times {10}^{-4}$

• A. $3.4\times {10}^{-5}$
• B. $4.3\times {10}^{-4}$
• C. $4.3\times {10}^{-5}$
• D. None of these

Answer 1

Answer: (B)

$4.3\times {10}^{-4}$

given, $3.0\times {10}^{-5}+4.0\times {10}^{-4}$

$=3.0\times {10}^{-1}x{10}^{-4}+4.0\times {10}^{-4}$
$=0.3\times {10}^{-4}+4.0\times {10}^{-4}$
$=4.3\times {10}^{-4}$