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Formula for mean in grouped data

= Zfx/ Zf

f = sum of the number of mice

= 35

Frequency = 39 + x

Mean = 7

Fx = 20 + 78 + 112 + 8x + 54

= 264 + 8x

7 = 264 + 8x/ 39 + x

7(39+x) = 264 + 8x

After solving you will get

x = 9

Hope this helps.

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9