The average age of nurses in a nursing home in 1982 was 50 years. In 1984, 20 nurses retired from their jobs, whose average age was 60 years. After a huge gap in 1987, 40 nurses were employed, whose average age was 38 years. The average age of all the nurses in 1990 was: 1982 সালে একটি নার্সিং হোমে নার্সদের গড় বয়স ছিল 50 বছর। 1984 সালে 20 জন নার্স অবসর নেয় যাদের গড় বয়স ছিল 60 বছর। 1987 সালে 40 জন নতুন নার্স যোগ দেয় যাদের গড় বয়স ছিল 38 বছর। 1990 সালে সকল নার্সের গড় বয়স কত?

Let number of nurses in 1982 = N

Average age in 1982 = 50

\[ \text{Total age in 1982} = 50N \]

From 1982 to 1990 = 8 years

If no one left or joined, total age in 1990 would be:

\[ 50N + 8N = 58N \]

In 1984 (after 2 years), 20 nurses retired.

Their average age in 1984 = 60

\[ \text{Total age removed} = 20 \times 60 = 1200 \]

From 1984 to 1990 = 6 more years.

If they had stayed, their age in 1990 would be:

\[ 1200 + (20 \times 6) = 1320 \]

So subtract 1320 from 58N:

\[ 58N - 1320 \]

In 1987 (after 5 years), 40 nurses joined.

Their average age in 1987 = 38

\[ \text{Total age added} = 40 \times 38 = 1520 \]

From 1987 to 1990 = 3 years.

\[ 1520 + (40 \times 3) = 1640 \]

Add this:

\[ 58N - 1320 + 1640 = 58N + 320 \]

Total nurses in 1990:

\[ N - 20 + 40 = N + 20 \]

Average age in 1990:

\[ \frac{58N + 320}{N + 20} \]

This still depends on N, so exact value cannot be uniquely found.

Correct Answer: Option D — Cannot be determined