CUET Preparation Today
CUET
-- Applied Mathematics - Section B2
Numbers, Quantification and Numerical Applications
If $2^{100}≡r$ mod 5, then r is equal to :
3
0
2
1
The correct answer is Option (4) → 1
$2^{100}≡r(mod\, 5)$
$⇒(2^4)^{25}≡r(mod\, 5)$
$⇒6≡r(mod\, 5)$
⇒ $r$ = remainder $(\frac{6}{5})=1$
