GMAT Practice Questions -4

1. If $n$ is a positive integer and $(n+3)(n+5)$ is odd, then $(n+4)(n+6)$ must be a multiple of which one of the following?
   
   
   1. $3$
   2. $ 5$
   3. $ 7$
   4. $ 8$
   5. $ 16$
   
   
2. The number of prime numbers divisible par 2 plus the number of prime numbers divisible by 5 is
   
   
   1. $0$
   2. $ 1$
   3. $ 2$
   4. $ 3$
   5. $ 4$
   
   
3. If $13x+17=0$, then $-13|x|$ equals which one of the following?
   
   
   1. $-\frac{17}{13}$
   2. $\frac{17}{13} $
   3. $17 $
   4. $13 $
   5. $-17 $
   
   
4. Which one of the following is divisible by both 2 and 3?
   
   
   1. $1007$
   2. $ 3096$
   3. $1616 $
   4. $ 2306$
   5. $ 1791$
   
   
5. Which one of the following equals the product of exactly two prime numbers?
   
   
   1. $13.6$
   2. $11.9$
   3. $17.21$
   4. $19.51$
   5. $17.23$
   
   
6. If $m$, $n$, and $p$ are different prime numbers, then the least common multiple of the the three numbers must equal which one of the following?
   
   
   1. $mn(p+n)$
   2. $m+n+p$
   3. $m+np$
   4. $m+n-p$
   5. $pnm$
   
   
7. Each of the positive integer $a$ and $b$ ends with the digit 3. With which one of the following numbers does $a-b$ ends?
   
   
   1. $0$
   2. $ 1$
   3. $ 2$
   4. $ 3$
   5. $ 4$
   
   
8. If $p-10$ is divisible by 4, then which one of the following must be divisible by 4?
   
   
   1. $p$
   2. $p-2$
   3. $p-6$
   4. $p+3$
   5. $p+8$