The mean number of pillows in nine boxes is 13. there are 12, 10, 15, 12, 13, 15, 11, and 13 pillow in eight boxes find the number pillows, in the last box.

16 is your answer

Step-by-step explanation:

There are 9 boxes in all, in which the total mean is 13. Let the last number be "x". Find the mean:

(12 + 10 + 15 + 12 + 13 + 15 + 11 + 13 + x)/9 = 13

Simplify. Combine like terms.

(101 + x)/9 = 13

Isolate the x. Note the equal sign. What you do to one side, you do to the other. Do the opposite of PEMDAS. First, multiply 9 to both sides

(101 + x)/9(9) = 13(9)

101 + x = 13(9)

101 + x = 117

Isolate the x. Subtract 101 from both sides

x + 101 = 117

x + 101 (-101) = 117 (-101)

x = 117 - 101

x = 16

16 is your answer

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step-by-step explanation: