Question

Simplify $1.24\times {10}^5+4.7\times {10}^3$ using scientific notation.

• A. $5.94\times {10}^5$
• B. $1.287\times {10}^3$
• C. $1.287\times {10}^5$
• D. $2.71\times {10}^5$

Answer 1

The correct option is C $1.287\times {10}^5$

$1.24\times {10}^5+4.7\times {10}^3$

First, we need to make the exponents with base 10 equal so that we can add the given numbers.

In $4.7\times {10}^3,$ move the decimal point two places to the left.
$\Rightarrow 0.047\times {10}^2\times {10}^3=0.047\times {10}^5$

Substituting $0.047\times {10}^5$ in the given expression, we get:

$1.24\times {10}^5+4.7\times {10}^3$
$=1.24\times {10}^5+0.047\times {10}^5$
$=(1.24+0.047)\times {10}^5$
$=1.287\times {10}^5$

Hence,the siplified value of the expression $1.24\times {10}^5+4.7\times {10}^{3}is1.287\times {10}^5.$