The Union Public Service Commission recently announced that the UPSC CSE 2024 Prelims will be held on June 16. Before the exam, candidates solve mock tests, revise the syllabus and look at the answer sheets of the previous years’ toppers. As candidates prepare for the upcoming exam, a CSAT question is doing the rounds on social media and might confuse you.
Brain Teaser: Can you solve this question just by doing mental calculations? (X/@UPSC_Notes)
The question was published by UPSC Notes with the title “CSAT Practical Question.”
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“If 3 raised to the power 2019 is divided by 10, what is the remainder?” is a question that has four options. They are: (a) 1, (b) 3, (c) 7 and (d) 9.
Check out the puzzle here:
Brain was distributed on April 21. It has since garnered over 1.1 lakh views and is still growing. Many even took to the comments section of the post to share their thoughts.
See how people reacted to this post here:
“Easy. The remainders repeat after every power of 3. That is, 3^1 gives 3 3^2 gives 9 Then 7 1 Then 3, 9, 7, 1 and this repeats. So 3^2020 or (3^ 4)^505 has a remainder of 1. So 3^2019 should have a remainder of 7 because the 7 comes before the 1 in the pattern,” the individual posted.
Another added: “7 is the correct answer.”
“The last digit of 3^n will be 3,9,7,1,3,9,7,1,3,9,7,1. Do you see a pattern? I bet you did. Only 3971 is repeated over and over. 3^multiples of 4 will end in 1. 3^2016 will end in 1. 3^2017 will end in 3. 3^2018 will end in 9. 3^2019 will end in 7 (Option C),” expressed a third .
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Source: newstars.edu.vn