Option 1 : 3

5^{19}(1 + 5^{2} + 5^{4})

⇒ 5^{19}(1 + 25 + 625)

⇒5^{19}(26 + 625)

⇒ 5^{19}(651)

**∴ 651 is divisible by 3.so, (5 ^{19 }+ 5^{21 }+ 5^{23}) is divisible by 3.**

India’s **#1 Learning** Platform

Start Complete Exam Preparation

Daily Live MasterClasses

Practice Question Bank

Mock Tests & Quizzes

Trusted by 2,17,91,872+ Students

Testbook Edu Solutions Pvt. Ltd.

1st & 2nd Floor, Zion Building,

Plot No. 273, Sector 10, Kharghar,

Navi Mumbai - 410210

[email protected]
Plot No. 273, Sector 10, Kharghar,

Navi Mumbai - 410210

Toll Free:1800 833 0800

Office Hours: 10 AM to 7 PM (all 7 days)