Question

The mean height of four boys is 145 cm . If yhe heights of three of them are 150 cm , 142 cm and 146 cm , find the height of fourth boy ​

Answer 1

Answer:

The answer of this question is 142 cm.

Step by step explanation:

Let the height of the fourth boy be x

Mean = Sum of all observations / Total number of observations

Mean = 150 cm + 142 cm + 146 cm + x cm / 4 = 145 cm

= 438 cm + x cm / 4 = 145 cm

= 438 cm + x cm = 145 × 4 cm

= 438 cm + x cm = 580 cm

= x cm = 580 cm - 438 cm

= x cm = 142 cm

Therefore, the height of the fourth boy is 142 cm

Answer 2

The height of the fourth boy = 142 cm

Step-by-step explanation:

Given,

The mean height of four boys = 145 cm

Let x be the height of the fourth boy.

To find, the height of fourth boy=?

We know that,

$Mean =\dfrac{Sum of all observations}{Total number of observations}$

∴ $\dfrac{150+142+146+x}{4}=145$

⇒ 438 + x = 145 × 4

⇒ 438 + x = 145 × 4

⇒ x = 580 - 438

⇒ x = 142

⇒ x  = 142 cm

∴ The height of fourth boy ​= 142 cm

Thus, the height of the fourth boy is "142 cm".