Question

plzzzz solve this question with step by step explanation ​

Answer 1

Answer:

The value of a = 5

Frequency of 30 = 28

Frequency of 70 = 24

Step-by-step explanation:

The table is given as -

x f

10 17

30 5a + 3

50 32

70 7a -11

90 19

Here, firstly we multiply values of x and f at each row .

The new table is shown as -

x f f *x

10 17 170

30 5a + 3 150a + 90

50 32 1600

70 7a -11 490a - 770

90 19 1710

Thus, summation of f *x is = 170 + 150a + 90 +1600 + 490a - 770 + 1710

= 640a + 2800

The summation of f = 17 + 5a + 3 + 32 + 7a -11 + 19

= 12a + 60

Thus, Mean is given by = ∑f *x/∑f

50 = (640a + 2800)/(12a + 60)

=> 600a + 3000 = 640a + 2800

=> 200 = 40a

=> a = 200/40

=> a = 5

Thus, frequency of 30 = 5a + 3

= 5 *5 + 3

= 28

Thus, frequency of 70 = 7a - 11

= 7 *5 - 11

= 24