This question was asked in GATE 2017, and the options were 90,91,92,93. I'm asking if there exists any mathematical formula to find this?
A 30 digit number, which starts with 4 and followed by 7, how many digits will be there when the 30 digit number will be cubed?
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elementary-number-theory
1 Answers
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Note that the number you state in the question is larger than $47 \times 10^{28}$ and smaller than $48 \times 10^{28}$. Now note the fact that $$10^6>48^3>47^3>10^5$$
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0But what can be the possible number of digits when 30 digit number is cubed? – 2017-02-12
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0@NilabjaBhattacharya Note that $$47^{3} \times \left(10^{28}\right)^3$$has its number of digits restricted. – 2017-02-12