Quantitative Aptitude Ques 1263
Question: The simplified value of $ (\sqrt{6}+\sqrt{10}-\sqrt{21}-\sqrt{35}) $ $ (\sqrt{6}-\sqrt{10}+\sqrt{21}-\sqrt{35}) $ is
Options:
A) 13
B) 12
C) 11
D) 10
Show Answer
Answer:
Correct Answer: D
Solution:
- $ (\sqrt{6}+\sqrt{10}-\sqrt{21}-\sqrt{35})(\sqrt{6}-\sqrt{10}+\sqrt{21}-\sqrt{36}) $ $ ={(\sqrt{6}-\sqrt{35}+(\sqrt{10}-\sqrt{21})} $
$ {(\sqrt{6}-\sqrt{35})-(\sqrt{10}-\sqrt{21})} $
$ ={{(\sqrt{6}-\sqrt{35})}^{2}}-{{(\sqrt{10}-\sqrt{21})}^{2}}=(6+35-2\sqrt{6}\cdot \sqrt{35}) $ $ -(10+21-2\sqrt{10}\cdot \sqrt{21}) $
$ =41-2\sqrt{210}-31+2\sqrt{210}=41-31=10 $