At the time of its formation in 1945, how many member countries did the United Nations Organisation (UNO) have?

Introduction / Context:
The foundation of the United Nations Organisation in 1945 is one of the most important events in modern world history. Questions relating to the number of founding members, the charter signing, and the main organs of the UN are very common in competitive exams. This particular question tests recall of the exact number of member countries that joined the United Nations at its birth in 1945.

Given Data / Assumptions:

• The year of formation of the United Nations is given as 1945.
• We are asked about the number of countries that were members at that time.
• Four options are provided: forty five, fifty one, forty eight, and fifty four.
• We assume that the candidate is familiar with basic UN history and charter facts.

Concept / Approach:
When the UN Charter was signed and the organisation formally came into existence, fifty one countries were original members. Over time, membership expanded significantly to include nearly all recognised sovereign states, but the founding figure of fifty one remains an important factual detail. The approach is therefore to remember or deduce this number rather than confuse it with later membership totals.

Step-by-Step Solution:
Step 1: Recall that the United Nations was created in 1945 after the Second World War to prevent another global conflict.Step 2: Remember that at its formation, there were fifty one founding members.Step 3: Compare this number with the answer options provided in the question.Step 4: Identify Fifty one as the correct option, expressed in words.Step 5: Confirm that other options correspond to incorrect membership counts and do not match the founding figure.

Verification / Alternative check:
A quick verification method is to recall that later milestones such as the admission of new states in the 1950s, decolonisation era, and post Cold War period increased UN membership to more than one hundred and ninety. In contrast, study materials and historical notes repeatedly mention fifty one original members in 1945. This clear distinction between founding membership and present membership helps confirm the correct number.

Why Other Options Are Wrong:
Option A, Forty five, is wrong because this number is lower than the actually recorded founding membership.Option C, Forty eight, is wrong because it does not match any standard milestone in UN membership history.Option D, Fifty four, is wrong because it is again a random higher figure and not the specific total at formation.

Common Pitfalls:
Students sometimes confuse the fifty one founding members with later membership totals or with numbers related to other organisations, such as the Commonwealth or regional groupings. Another common error is to assume that the present day membership count was also the starting figure, which is not correct. To avoid these mistakes, aspirants should create a simple timeline of UN membership growth with a clear note that the starting point in 1945 was fifty one countries.

Final Answer:
Fifty one