Question

. If a letter is drawn at random from the letters in word 'ERROR', then the letters which have equal probability of being drawn are (a) E and o (b) R and E (c) O and R (d) E, R and O​

Answer 1

$\sf{(a) E \: and \: O}$

Explanation-

Given-

• Given Word → ERROR

• Total Number of letters = 5

• Number of E = 1

Solution-

Formula-

$\boxed{\sf Probability \: of \: an \: event= \frac{favourable \: events}{Total \: number \: of \: events}}$

Using Formula-

Number of E = 1

$\implies$Probability of E = 1/5

Number of R = 3

$\implies$Probability of R = 3/5

Number of O = 1

$\implies$Probability of O = 1/5

$\therefore{ \bf{Probability \: of \: E \: and \: O \: is \: same}}$

Answer 2

Given-

Given Word $=$ ERROR

Total Number of letters $= 5$

To find: the letters that have equal probability of being drawn.

Solution:

Know that,

Number of letter E in the given word $= 1$

Number of letter R in the given word $= 3$

Number of letter E in the given word $= 1$

Apply formula,

$\[{\rm{Probability = }}\frac{{{\rm{Probability}}\,{\rm{of}}\,{\rm{an}}\,{\rm{event}}}}{{{\rm{Total}}\,{\rm{outcomes}}}}\]$

Find the probability of letter E being drawn.

$\[ = \frac{1}{5}\]$

Find the probability of letter R being drawn.

$\[ = \frac{3}{5}\]$

Find the probability of letter O being drawn.

$\[ = \frac{1}{5}\]$

Observe that, letter E and letter O have equal probability of being chosen.

Hence, the correct answer is option (a). i.e., E and O.