Power Play (Exponents) | FIO

Question 17

What was the date 1 arab/1 billion seconds ago?

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Solution

FIO-17

Chapter: POWER PLAY (EXPONENTS)
Class: 8 (Class 8)
Category: figure_it_out


Question

What was the date 1 arab/1 billion seconds ago?


We need to convert a very long time duration from seconds into years, months, and days to find a specific date in the past.

Step 1 — Convert 1 billion seconds to years

First, let us understand the given time. 1 arab is the same as 1 billion. So, we are talking about 10910^9 seconds.

We need to find out how many seconds are in one year. We know that 1 minute has 60 seconds. 1 hour has 60 minutes. So, 1 hour = 60×60=360060 \times 60 = 3600 seconds. 1 day has 24 hours. So, 1 day = 24×3600=86,40024 \times 3600 = 86,400 seconds. To account for leap years, we use an average of 365.25 days in a year. So, 1 year = 365.25×86,400365.25 \times 86,400 seconds.

1 year=365.25×24×60×60 seconds1 \text{ year} = 365.25 \times 24 \times 60 \times 60 \text{ seconds}

=31,557,600 seconds= 31,557,600 \text{ seconds}

Now, we can find how many years are in 10910^9 seconds. We divide the total seconds by the seconds in one year.

Number of years=1,000,000,00031,557,600\text{Number of years} = \frac{1,000,000,000}{31,557,600}

=31.69987... years= 31.69987... \text{ years}

We can round this to one decimal place.

31.7 years\boxed{31.7 \text{ years}}

Step 2 — Calculate the past date

Let us assume today's date is July 29, 2025. We need to go back 31.7 years. This means we go back 31 full years and then an additional 0.7 years.

First, subtract the 31 full years from the current date. The year changes from 2025 to 2025312025 - 31.

202531=19942025 - 31 = 1994

So, after subtracting 31 years, the date is July 29, 1994.

Now, we need to go back an additional 0.7 years. To convert 0.7 years into months, we multiply by 12.

0.7 years×12 months/year=8.4 months0.7 \text{ years} \times 12 \text{ months/year} = 8.4 \text{ months}

The problem asks us to consider this as approximately 8.5 months. So, we need to go back 8.5 months from July 29, 1994.

Let us go back 8 full months from July 29, 1994: July (7th month) - 8 months = November (11th month of the previous year). So, 8 months before July 29, 1994, is November 29, 1993.

Now, we need to go back an additional 0.5 months. An average month has about 30 days. So, 0.5 months is approximately 0.5×30=150.5 \times 30 = 15 days. We subtract 15 days from November 29, 1993.

29 days15 days=14 days29 \text{ days} - 15 \text{ days} = 14 \text{ days}

So, the date would be around November 14, 1993. This is approximately mid-November 1993.

Answer

The date 1 arab / 1 billion seconds ago was around mid-November 1993.

More questions in FIO

Q1

Express the following in exponential form:

(i) 6×6×6×66 \times 6 \times 6 \times 6

(ii) y×yy \times y

(iii) b×b×b×bb \times b \times b \times b

(iv) 5×5×7×7×75 \times 5 \times 7 \times 7 \times 7

(v) 2×2×a×a2 \times 2 \times a \times a

(vi) a×a×a×c×c×c×c×da \times a \times a \times c \times c \times c \times c \times d

Q2

Express each of the following as a product of powers of their prime factors in exponential form:

(i) 648

(ii) 405

(iii) 540

(iv) 3600

Q3

Write the numerical value of each of the following:

(i) 2×1032 \times 10^3

(ii) 72×237^2 \times 2^3

(iii) 3×443 \times 4^4

(iv) (3)2×(5)2(-3)^2 \times (-5)^2

(v) 32×1043^2 \times 10^4

(vi) (2)5×(10)6(-2)^5 \times (-10)^6

Q4

Find out the units digit in the value of 2224÷4322^{224} \div 4^{32}? [Hint: 4=224 = 2^2]

Q5

There are 5 bottles in a container. Every day, a new container is brought in. How many bottles would there be after 40 days?

Q6

Write the given number as the product of two or more powers in three different ways. The powers can be any integers.

(i) 64364^3 (ii) 1928192^8 (iii) 32532^{-5}

Q7

Examine each statement below and find out if it is 'Always True', 'Only Sometimes True', or 'Never True'. Explain your reasoning.

(i) Cube numbers are also square numbers.

(ii) Fourth powers are also square numbers.

(iii) The fifth power of a number is divisible by the cube of that number.

(iv) The product of two cube numbers is a cube number.

(v) q46q^{46} is both a 4th power and a 6th power (qq is a prime number).

Q8

Simplify and write these in the exponential form.

(i) 102×10510^{-2} \times 10^{-5}

(ii) 57÷545^7 \div 5^4

(iii) 97÷949^{-7} \div 9^4

(iv) (132)3(13^{-2})^{-3}

(v) m5n12(mn)9m^5n^{12}(mn)^9

Q9

If 122=14412^2 = 144 what is

(i) (1.2)2(1.2)^2

(ii) (0.12)2(0.12)^2

(iii) (0.012)2(0.012)^2

(iv) 1202120^2

Q10

Circle the numbers that are the same—

24×362^4 \times 3^6            64×326^4 \times 3^2            6106^{10}            182×6218^2 \times 6^2            6246^{24}

Q11

Identify the greater number in each of the following—

(i) 434^3 or 343^4

(ii) 282^8 or 828^2

(iii) 1002100^2 or 21002^{100}

Q12

A dairy plans to produce 8.5 billion packets of milk in a year. They want a unique ID (identifier) code for each packet. If they choose to use the digits 0–9, how many digits should the code consist of?

Q13

64 is a square number (828^2) and a cube number (434^3). Are there other numbers that are both squares and cubes? Is there a way to describe such numbers in general?

Q14

A digital locker has an alphanumeric (it can have both digits and letters) passcode of length 5. Some example codes are G89P0, 38098, BRJKW, and 003AZ. How many such codes are possible?

Q15

The worldwide population of sheep (2024) is about 10910^9, and that of goats is also about the same. What is the total population of sheep and goats?

(ii) 20920^9

(ii) 101110^{11}

(iii) 101010^{10}

(iv) 101810^{18}

(v) 2×1092 \times 10^9

(vi) 109+10910^9 + 10^9

Q16

Calculate and write the answer in scientific notation:

(i) If each person in the world had 30 pieces of clothing, find the total number of pieces of clothing.

(ii) There are about 100 million bee colonies in the world. Find the number of honeybees if each colony has about 50,000 bees.

(iii) The human body has about 38 trillion bacterial cells. Find the bacterial population residing in all humans in the world.

(iv) Total time spent eating in a lifetime in seconds.

Q17

What was the date 1 arab/1 billion seconds ago?

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