Question : If
Option 1: 140
Option 2: 70
Option 3: 100
Option 4: 120
Correct Answer: 140
Solution :
Subtract 5 in equation (1) on both sides
⇒
Now, take
So, the equation becomes
⇒
Cubing both sides
⇒
⇒
⇒
Hence, the correct answer is 140.