On one page of a telephone directory, there are 200 phone numbers. The frequency distribution of their unit's digits is given below:

$\begin{matrix} Unit's digit & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 Frequency & 19 & 22 & 23 & 19 & 21 & 24 & 23 & 18 & 16 & 15 \end{matrix}$

One of the numbers is chosen at random from the page. What is the probability that the unit's digit of the chosen number is (i) 5? (ii) 8?

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Solution

ANSWER:
Total phone numbers on the directory page = 200
(i) Number of numbers with units digit 5 = 24
Let E 1 be the event that the units digit of selected number is 5.
∴ Required probability = P ( E 1 ) = $\frac{24}{200} = 0.12$
(ii) Number of numbers with units digit 8 = 16
Let E 2 be the event that the units digit of selected number is 8.
∴ Required probability = P ( E 2 ) = $\frac{16}{200} = 0.08$

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Similar questions

On one page of a telephone directory, there are 200 phone numbers. The frequency distribution of their unit's digits is given below:

$\begin{matrix} Unit's digit & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 Frequency & 19 & 22 & 23 & 19 & 21 & 24 & 23 & 18 & 16 & 15 \end{matrix}$

One of the numbers is chosen at random from the page. What is the probability that the unit's digit of the chosen number is (i) 5? (ii) 8?

Units digit	0	1	2	3	4	5	6	7	8	9
Frequency	19	22	23	19	21	24	23	18	16	15

Unit digit	0	1	2	3	4	5	6	7	8	9
Frequency	22	26	22	22	20	10	14	28	16	20

Unit digit	0	1	2	3	4	5	6	7	8	9
Frequency	35	21	28	30	25	14	16	38	38	55

Unit place digit	0	1	2	3	4	5	6	7	8	9
Frequency	19	16	18	21	14	11	15	16	13	17

\frac{2}{5}

\frac{3}{32}

\frac{3}{80}

\frac{29}{32}

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