Question

if mean = 18, find x and y

Answer 1

Here we will require two linear equations to solve for two variables


According to the question
7+x+9x+13+x+20+y+4=64   [Number of students]
x+y=11..........................(i)

and by using mean
$\frac{[7*12]+[x*14]+[9*16]+[13*18]+[20*20]+[y*22]+[4*24]}{64}=18$
$84+14x+144+234+400+22y+96=[18 *64]$
$14x+22y=194$
$7x+11y=97.............(ii)$

performing (ii)-7(i)
4y=20
y=5

substituting in (i) we get
x=6

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Answer 2

$<b><u><i>$Refer to the attachment, the mean is given and by using mean method we got the value of x = 6 , and y = 5