Let the missing number be x
Mean is the total sum of data over the number of data therefore,
(11+20+x+3+1) / 5 = 9
Then simplify
(35 + x) / 5 = 9
Then multiply 5 to both sides
35 + x = 45
Then subtract 35 to both sides to find x
X= 10
Hope this helps!
p = total # of pages
2/5p + 32 = 310 (She read 2/5 of the book, read an addition of 32 pages, and she read a total of 310 pages.) Subtract 32 on both sides
2/5p = 278 (multiply each side by 5/2 to get p by itself)
p = 695
Ooh, fun
geometric sequences can be represented as

so the first 3 terms are



the sum is -7/10

and their product is -1/125

from the 2nd equation we can take the cube root of both sides to get

note that a=ar/r and ar²=(ar)r
so now rewrite 1st equation as

subsituting -1/5 for ar

which simplifies to

multiply both sides by 10r
-7r=-2-2r-2r²
add (2r²+2r+2) to both sides
2r²-5r+2=0
solve using quadratic formula
for


so
for 2r²-5r+2=0
a=2
b=-5
c=2




so

or

use them to solve for the value of a


try for r=2 and 1/2

or

test each
for a=-1/10 and r=2
a+ar+ar²=

it works
for a=-2/5 and r=1/2
a+ar+ar²=

it works
both have the same terms but one is simplified
the 3 numbers are

,

, and
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