For the following questions answer them individually
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?
The net power of the number of lenses in an optical instrument is the ........... of the individual powers of lenses.
Meena is 15 years elder to Reena. 15 years back she wasthrice as old as Reena. What is Reena's present age?
A vessel contains some amount of pure milk. 8 litres of water is added to dilute the milk, after taking out 8 litres of pure milk. Once again 8 litres of the resulting mixture is removed and 8 litres of water is added. The amount of pure milk in the second mixture is 49 litres. What amount of pure milk was in the container originally ?
