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14. Once upon a time, a king went to the jungle for hunting. When he was hiding behind a tree,
a wolf attacked him. He shouted for help, and at the same time, a man who was passing from
the jungle listened a voice. He ran towards the voice and saved the life of the king. The king
was very grateful and asked him for a reward. The king told him whatever you want, just tell. CASE STUDY
Initially, the man does not refuse the king’s order. So, he said, you will give me just one rice
grain for the first day, and from the next day you will give me double what you gave me on
the previous day for 30 days. The king laughs loudly at his innocence and agrees to give rice
to him for 30 days as the man.

Based on the above information, answer the following questions:
(a) How many rice grains did the king give to the man in the first 5 days?

(b) On which day the man will get the half number of rice grains that will be received on 30th day?
(c) On 30th day, how many rice grains will the man will get from the king? Was the man act innocent
that time?

Mental Maths

1. Simplify: (6 – 3 ) x (–2) 3
2
2
 2 2  3 4
2. Find the reciprocal of the rational number   ÷   .

2
3

3 2
2 3
3. Are x y and x y the same? If yes, give reasons for your justification.
3
4
7
4. Are the answers of all the terms (1) , (–1) , (–1) positive?
n
m
5. m > n is true, if m = 2 and n = 3, but false if m = 3 and n = 2? Is the statement correct?
www
MAths connect
Bacteria are small, single-celled organisms. They are found almost
everywhere on Earth and are vital to the planet's ecosystems.
Most bacteria reproduce through simple cell division known as binary fission.
Each species reproduces best at a specific temperature and moisture level.
Suppose bacteria can divide in every 15 minutes.
So, 1 bacterium can multiply to 3 in 15 minutes.
9 in 30 minutes, and so on.
How many bacteria will there be in 8 hours? Write your answer using
exponents, and then evaluate.

Brain Sizzlers

The speed of light in vacuum is 3 × 10 m/s. Sunlight takes about 8 minutes to reach the earth. Express the
8
distance of the Sun from Earth in standard form.

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