The mean height of 5 students is 140 cm. If height of one student is 156 cm, the mean height of remaining students is :

1. 74 cm

2. 136 cm

3. 16 cm

4. 80 cm

The mean age of eight boys is 16 years. If two more boys, with ages 18 years and 14 years, join them, the resulting mean age is :

1. 18 years

2. 14 years

3. 16 years

4. 32 years

The mean value of 15 numbers is 20. If one of these numbers is wrongly taken as 45 instead of 15, the correct mean is :

1. 30

2. 15

3. 20

4. 18