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

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

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

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?

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}

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

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