Questions asking to compute a specific remainder, residue, or value of an expression modulo a given integer, typically involving exponentiation or factorial computations.
The number of positive integers $n$ less than or equal to 22 such that 7 divides $n ^ { 5 } + 4 n ^ { 4 } + 3 n ^ { 3 } + 2022$ is (A) 7 (B) 8 (C) 9 (D) 10
Suppose $x$ and $y$ are positive integers. If $4 x + 3 y$ and $2 x + 4 y$ are divided by 7, then the respective remainders are 2 and 5. If $11 x + 5 y$ is divided by 7, then the remainder equals (A) 0. (B) 1. (C) 2. (D) 3.
Let $N$ be a 50 digit number. All the digits except the 26th one from the right are 1. If $N$ is divisible by 13, then the unknown digit is (a) 1 . (B) 3 . (C) 7 . (D) 9 .
Let $A = \{ n \in N : n$ is a 3-digit number $\}$, $B = \{ 9 k + 2 : k \in N \}$ and $C = \{ 9 k + l : k \in N \}$ for some $l ( 0 < l < 9 )$. If the sum of all the elements of the set $A \cap ( B \cup C )$ is $274 \times 400$, then $l$ is equal to
Let the number $( 22 ) ^ { 2022 } + ( 2022 ) ^ { 22 }$ leave the remainder $\alpha$ when divided by 3 and $\beta$ when divided by 7 . Then $\left( \alpha ^ { 2 } + \beta ^ { 2 } \right)$ is equal to (1) 20 (2) 13 (3) 5 (4) 10
$$\begin{aligned}
& 2 ^ { x } \equiv 1 ( \bmod 7 ) \\
& 3 ^ { y } \equiv 4 ( \bmod 7 )
\end{aligned}$$ For the smallest positive integers x and y satisfying these congruences, what is the difference $y - x$? A) 5 B) 4 C) 3 D) 2 E) 1
$$\lim _ { x \rightarrow \infty } \frac { e ^ { - 3 x } + e ^ { 2 x } } { \ln x + 3 e ^ { 2 x } }$$ What is the value of this limit? A) $\frac { 1 } { 2 }$ B) $\frac { 3 } { 2 }$ C) $\frac { 1 } { 3 }$ D) 0 E) 1
Let $a$ and $b$ be natural numbers such that $$\begin{aligned}& 4 \cdot a \equiv 2 ( \bmod 11 ) \\& 4 \cdot b \equiv 5 ( \bmod 7 )\end{aligned}$$ the following congruences are given.\ Accordingly, what is the smallest value that the sum $\mathbf{a+b}$ can take?\ A) 7\ B) 9\ C) 11\ D) 13\ E) 15