The mean of the following distribution is 50 . x 10 30 50 70 90 f 17 5 a + 3 32 7 a - 11 19 Find the value of a and hence the frequencies of 30 and 70

Given, x i f i f i × x i 10 17 170 30 5 a + 3 150 a + 90 50 32 1600 70 7 a - 11 490 a - 770 90 19 1710 ∑ f i = 60 + 12 a ∑ ( f i × x i ) = 2800 + 640 a Given mean is = 50 Mean, x = ∑ f i × x i ∑ f i 50 = 2800 + 640 a 60 + 12 a 50 × 60 + 12 a = 2800 + 640 a 3000 + 600 a = 2800 + 640 a 640 a - 600 a = 3000 - 2800 40 a = 200 a = 200 40 = 5 Therefore, the required value of a is 5 . ∴ f 30 = 5 a + 3 = 5 × 5 + 3 = 28 & f 70 = 7 a - 11 = 7 × 5 - 11 = 35 - 11 = 24

R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B

Author:R S Aggarwal & Veena Aggarwal

R S Aggarwal Mathematics Solutions for Exercise - R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B

Attempt the free practice questions from Exercise 2: EXERCISE 18B with hints and solutions to strengthen your understanding. Secondary School Mathematics FOR CLASS 9 solutions are prepared by Experienced Embibe Experts.

Questions from R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B with Hints & Solutions

HARD

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 6

Find the mean of daily wages of $40$ workers in a factory as per data given below:

Daily wages (in $₹$ ) $(x_{i})$	$250$	$300$	$350$	$400$	$450$
Number of workers $(f_{i})$	$8$	$11$	$6$	$10$	$5$

HARD

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 8

If the mean of the following data is $8$ , find the value of $p$ .

$x_{i}$	$3$	$5$	$7$	$9$	$11$	$13$
$f_{i}$	$6$	$8$	$15$	$p$	$8$	$4$

HARD

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 9

Find the missing frequency $p$ for the following frequency distribution whose mean is $28.25$ .

$x$	$15$	$20$	$25$	$30$	$35$	$40$
$f$	$8$	$7$	$p$	$14$	$15$	$6$

MEDIUM

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 10

Find the value of $p$ for the following frequency distribution whose mean is $16.6$ .

$x$	$8$	$12$	$15$	$p$	$20$	$25$	$30$
$f$	$12$	$16$	$20$	$24$	$16$	$8$	$4$

HARD

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 11

Find the missing frequencies in the following frequency distribution whose mean is $34$ .

$x$	$10$	$20$	$30$	$40$	$50$	$60$	Total
$f$	$4$	$f_{1}$	$8$	$f_{2}$	$3$	$4$	$35$

HARD

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 12

Find the missing frequencies in the following frequency distribution whose mean is $50$ .

$x$	$10$	$30$	$50$	$70$	$90$	Total
$f$	$17$	$f_{1}$	$32$	$f_{2}$	$19$	$120$

MEDIUM

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 13

Find the greatest value of $p$ , when the mean of the following distribution is $20$ .

$x$	$15$	$17$	$19$	$20 + p$	$23$
$f$	$2$	$3$	$4$	$5 p$	$6$

MEDIUM

9th CBSE

IMPORTANT

Secondary School Mathematics FOR CLASS 9>Chapter 18 - Mean, Median and Mode of Ungrouped Data>EXERCISE 18B>Q 14

The mean of the following distribution is $50$ .

$x$	$10$	$30$	$50$	$70$	$90$
$f$	$17$	$5 a + 3$	$32$	$7 a - 11$	$19$

Find the value of $a$ and hence the frequencies of $30$ and $70$

R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B

R S Aggarwal Mathematics Solutions for Exercise - R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B

Questions from R S Aggarwal and Veena Aggarwal Solutions for Exercise 2: EXERCISE 18B with Hints & Solutions

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