JEE Main 2022 · 30 Jun · Shift 1 · Mathematics Q29

MathematicsInteger+4 / -1Question 29 of 90

The probability distribution of X is :

X	0	1	2	3
P(X)	$\frac{1-d}4$	$\frac{1+2d}4$	$\frac{1-4d}4$	$\frac{1+3d}4$

For the minimum possible value of d, sixty times the mean of X is equal to ______.

Your answer

Answer and worked solution

Official answer: 75

Valid d. All probabilities non-negative: $-\frac13\le d\le\frac14$ , so the minimum is $d=-\frac13$ .

Mean $\frac{6+3d}4=\frac54$ ; sixty times is 75.

Answer: 75

JEE Main 2022 · 30 Jun · Shift 1, Mathematics question 29