Step 1:

Let $X$ be the random variable denoting the weight of a male student in the college.

$X\sim N(150,15^2)$

Step 2:

To find the probability that a student weighs more than 185 pounds (i.e) $P(X > 185)$

When $X=185$

$Z=\large\frac{185-151}{15}$

$\;\;\;=\large\frac{34}{15}$

$\;\;\;=2.27$

$P(X > 185)=P(Z >2.27)$

$\qquad\qquad\;\;\;=0.5-P(0 < Z < 2.27)$

$\qquad\qquad\;\;\;=0.5-0.4884$

$\qquad\qquad\;\;\;=0.0116$

Step 3:

The number of male students in the college=500

$\therefore$ the number of students expected to weigh more than 185 pounds =$500\times 0.0116$

$\Rightarrow 6$(approx)