The average of five numbers is 57.8. The average of the first and the second number is 77.5, and the average of the fourth and the fifth number is 46. What is the third number? পাঁচটি সংখ্যার গড় 57.8। প্রথম ও দ্বিতীয় সংখ্যার গড় 77.5 এবং চতুর্থ ও পঞ্চম সংখ্যার গড় 46। তৃতীয় সংখ্যাটি কত?

Average of 5 numbers = 57.8

\[ \text{Total of 5 numbers} = 5 \times 57.8 = 289 \]

Average of 1st and 2nd numbers = 77.5

\[ \text{Sum of 1st and 2nd} = 2 \times 77.5 = 155 \]

Average of 4th and 5th numbers = 46

\[ \text{Sum of 4th and 5th} = 2 \times 46 = 92 \]

Let the 3rd number be \( x \).

\[ 155 + x + 92 = 289 \]

\[ 247 + x = 289 \]

\[ x = 42 \]

Correct Answer: Option C