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Find the greatest number by which when the numbers 57, 95 and 211 are divided, it leaves the same remainder in each case.
4
2
1
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2
Calculate the differences between the numbers: (95тИТ57)=38, (211тИТ95)=116, and (211тИТ57)=154. The HCF of these differences is the required number.
The numbers are 57, 95, and 211. We need to find the greatest number that leaves the same remainder when these numbers are divided by it.
Greatest┬аNumber=HCF((yтИТx),(zтИТy),(zтИТx))
Calculate the differences between the numbers: (95тИТ57)=38, (211тИТ95)=116, and (211тИТ57)=154. The HCF of these differences is the required number.
Many students mistake this for finding the HCF of the numbers themselves (57, 95, 211), which is incorrect because the problem asks for a number that leaves the 'same remainder'.
Calculate the differences
To find the divisor that leaves the same remainder, we find the differences between the numbers: 95тИТ57=38 and 211тИТ95=116 and 211тИТ57=154.
95тИТ57=38,211тИТ95=116,211тИТ57=154
Find the HCF of the differences
We need the Highest Common Factor (HCF) of 38, 116, and 154.
HCF(38,116,154)
Perform prime factorization
Factorize the differences: 38=2├Ч19, 116=22├Ч29, 154=2├Ч7├Ч11. Re-checking the differences: the HCF of 38, 116, 154 is indeed 2.
38=2├Ч19,116=2├Ч58=2├Ч2├Ч29,154=2├Ч77=2├Ч7├Ч11
Conclusion
The only common factor shared by 38, 116, and 154 is 2. Thus, the greatest number is 2.
HCF=2
B is correct because the Highest Common Factor (HCF) of the differences (95тИТ57)=38, (211тИТ95)=116, and (211тИТ57)=154 is 2.
This concept of 'equal remainder' frequently appears in aptitude tests; always remember the formula: find the HCF of the differences between the numbers pairwise.