Question

Add the following numbers:
$6.5\times {10}^{21}$ and $1.1\times {10}^{22}$

• A. $7.6\times {10}^{21}$
• B. $7.6\times {10}^{22}$
• C. $17.5\times {10}^{22}$
• D. $17.5\times {10}^{21}$

Answer 1

The correct option is D $17.5\times {10}^{21}$

Given numbers are $6.5\times {10}^{21}$ and $1.1\times {10}^{22}$
$6.5\times {10}^{21}$ + $1.1\times {10}^{22}$
$=6.5\times {10}^{21}$ + $1.1\times 10\times {10}^{21}$
$=6.5\times {10}^{21}$ + $11\times {10}^{21}$
$=(6.5+11)\times {10}^{21}$
$=17.5\times {10}^{21}$
Hence, D will be correct answer.