Question

A pair of dice is rolled 5 times. let getting a total of 5 in a single throw is considered as success. If probability of getting atleast four success is $\frac{x}{3}$ then x is equal to

• A. $\frac{41}{9^{5}}$
• B. $\frac{41}{9^{4}}$
• C. $\frac{123}{9^{5}}$
• D. $\frac{123}{9^{4}}$

Answer 1

Answer: (C)

$\frac{123}{9^{5}}$

Answer 2

The P(success) = $\frac{4}{36}$ = $\frac{1}{9}$
P(atleast for the four success) = 5C4$(\frac{1}{9})^{4}$ . $\frac{8}{9}$+$(\frac{1}{9})^{3}$ = $\frac{x}{3}$
⇒ x = $\frac{41\times 3}{9^{5}}$ = $\frac{123}{9^{5}}$