The mean of the heights of 6 girls is 148 cm. If the individual heights of five of them are 142 cm, 154 cm, 146 cm, 145 cm and 150 cm, find the height of the sixth girl.

Mean height of 6 girls = 148 cm

Number of girls (n) = 6

Heights of 5 girls:

142 cm, 154 cm, 146 cm, 145 cm, 150 cm

Let height of the sixth girl be x cm.

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

⇒ 148 = $\dfrac{142 + 154 + 146 + 145 + 150 + x}{6}$

⇒ 148 × 6 = 737 + x

⇒ 888 = 737 + x

⇒ x = 888 - 737 = 151.

Hence, height of the sixth girl = 151 cm.