JEE Main 2025 Mathematics question
If the mean and the variance of 6, 4, a, 8, b, 12, 10, 13 are 9 and 9.25 respectively, then a + b + ab is equal to :
Answer: (1)
Solution
Mean gives a+b=19; variance gives ; solving a=7, b=12, so a+b+ab = 19+84 = 103.