1.

`7^(103)` when divided by 25 leaves the remainder .A. 20B. 16C. 18D. 15

Answer» Correct Answer - c
We have,
` 7^(103) = 7(49)^(51)`
`rArr 7^(103) = 7(50 -1)^(51)`
` rArr 7^(103) = 7{""^(51)C_(90)(50)^(51) - ""^(51)C_(r)(50)^(50) + ""^(51)C_(2)(50)^(49)...-1}`
` rArr 7^(103) = 7{(50)^(51) - ""^(51)C_(1)(50)^(50) + ""^(51)C_(2)(50)^(49)...}-7`
`rArr 7^(103) = 7{(50)^(51) - ""^(51)C_(1)(50)^(50) + ""^(51)C_(2)(50)^(49)...}-7 - 18 + 18`
`rArr 7^(103) = 7{(50)^(51) - ""^(51)C_(1)(50)^(50) + ""^(51)C_(2)(50)^(49)...}-25 + 18`
`rArr 7^(103)` = Multiple of 25 + 18
Hence, remainder = 18.


Discussion

No Comment Found

Related InterviewSolutions