Statistics-And-Probability Question 625

Question: In a test of statistics marks were awarded out of 40. The average of 15 students was 38. Later it was decided to give marks out of 50. The new average marks will be

Options:

A) 40

B) 47.5

C) 95

D) 41.5

Show Answer

Answer:

Correct Answer: B

Solution:

[b] Let a student gets x marks out of 40. He gets $ \frac{5x}{4} $ marks out of 50. Thus, each observation will be multiplied by $ \frac{5}{4}. $ Hence, mean is also multiplied by $ \frac{5}{4} $ giving mean $ =38\times \frac{5}{4}=47.5. $