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09 Feb 2020, 21:52
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A number N is formed by placing first 100 integers in order (N = 1234567891011121314…………). If N is a 150 digit number, what is the remainder when N is divided by 10?
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums! :please
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums! :please
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shameekv1989
09 Feb 2020, 22:22
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Anurag06
A number N is formed by placing first 100 integers in order (N = 1234567891011121314…………). If N is a 150 digit number, what is the remainder when N is divided by 10?
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums!
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums!
N = 150 digit integer
Since 1st 9 digits are single-digit and rest are 2 digits
150 - 9 = 141 are formed from 2 digits
every 10-19, 20-29, 30-39 ... will form 20 digits
141/20 = 7 + 1(left over)
Hence, 10-79 will form 140 digits and the last digit will be 8
Answer - D
09 Feb 2020, 22:48
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Anurag06
Anurag06
A number N is formed by placing first 100 integers in order (N = 1234567891011121314…………). If N is a 150 digit number, what is the remainder when N is divided by 10?
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums!
A) 1
B) 3
C) 7
D) 8
E) 9
Would Appreciate if someone helps with faster and easier method on this type of sums!
Hello Gurus Bunuel VeritasKarishma ScottTargetTestPrep
Any tips and take overs on this types please?
Division by 10 means it is looking for the units digit of N.
The units digit depends on the last integer that makes up N. The last integer depends on the number of digits previous integers have.
1 - 9 have 1 digit each so 9 digits total.
10 - 99 have 2 digits each so 180 digits total.
Since N has 150 digits, it will have the first 9 1-digit numbers and 70 two digit numbers. the 150th digit will be the first digit of the 71st number .
N = 1234...9101112....7778798
This adds up to 150 digits. when divided by 10, the remainder will be the units digit - 8.
Answer (D)
