Question

Q4 - Exam prep: Missing values

Audrey measures all 7 pencils in her pencil case and writes the first 6 lengths down.
12.4 cm, 12.6 cm, 13 cm, 13.4 cm, 13.5 cm, 13.3 cm
Audrey calculates the mean length of all 7 pencils to be 13.1 cm.
Find the length of the missing pencil.
cm
[2]

Answer 1

the missing pencil length is 13.5 cm

Explanation:

The computation of the length of the missing pencil is shown below:

Let us assume the missing pencil be x

Now

(12.4 cm + 12.6 cm + 13 cm + 13.4 cm + 13.5 cm + 13.3 cm + x) ÷ 7 = 13.1 cm

(78.2 cm + x) ÷ 7 = 13.1 cm

78.2 cm + x = 91.7 m

So, x would be

= 91.7 cm - 78.2 cm

= 13.5 cm

hence, the missing pencil length is 13.5 cm