To find $n(B)$, we can use the formula for the union of two sets $A$ and $B$:

$n(A \cup B) = n(A) + n(B) - n(A \cap B)$

Given:

• $n(A) = 1700$
• $n(A \cup B) = 2250$
• $n(A \cap B) = 320$

We need to find $n(B)$. Plugging in the values:

$2250 = 1700 + n(B) - 320$

Simplify the equation:

$2250 = 1380 + n(B)$

Now, solve for $n(B)$:

$n(B) = 2250 - 1380 = 870$

So, $n(B) = 870$.

Would you like more details or have any questions?

Here are 5 related questions:

1. What is the formula for the union of three sets?
2. How would you calculate $n(A \cup B \cup C)$ if given $n(A)$, $n(B)$, $n(C)$, and the intersections?
3. What does $n(A \cap B) = 0$ imply about the sets $A$ and $B$?
4. How would you find $n(A \cup B)$ if $n(B)$ was unknown but $n(A)$ and $n(A \cap B)$ were given?
5. How can Venn diagrams be used to represent these set operations?

Tip: Always double-check your work by substituting your results back into the original equation to ensure accuracy.