Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:
If $m$ and $n$ are positive integers, then the digit in the unit's place of $5^{n}+6^{m}$ is always
(a)1
(b)5
(c)6
(d)$n+m$
Answer
Answer (as printed): A
Explanation
In $5^{n}$ we have 5 as unit digit and in $6^{m}$ we have 6 as unit digit.∴ Unit digit in $\left(5^{n}+6^{m}\right)=$ Unit digit in $(5+6)=$ Unit digit in $11=1$.
Explanation as extracted from the printed page; notation may be imperfect.