Question

The square root of $121$ can be confirmed after repeated subtraction of the first _______ odd numbers

• A. $10$
• B. $9$
• C. $11$
• D. $8$

Answer 1

The correct option is C $11$

$121-1=120$
$120-3=117$
$117-5=112$
$112-7=105$
$105-9=96$
$96-11=85$
$85-13=72$
$72-15=57$
$57-17=40$
$40-19=21$
$21-21=0$
We get 0 after the repeated subtraction of $11$ consecutive odd numbers. Hence, the square root of $121$ can be confirmed after repeated subtraction of the first $11$ odd numbers.