A tree on first day grows 1/2 of its size second day 1/3rd of its size...
Let initially size of tree be 'x' , no. of days be 'n'.
1st day increment in size of tree = (1/2)x
After 1st day , size of tree = x+(1/2)x= (3/2)x
2nd day increment in size of tree = (1/3)*(3/2)x=(1/2)x
After 2nd day , size of tree = (3/2)x+(1/2)x=2x
3rd day increment in size of tree =(1/4)*2x=(1/2)x
After 3rd day , size of tree = 2x+(1/2)=(5/2)x
We can see that every day tree grows (1/2)x in size.
therefore , according to given condition
x+ (1/2)x*n=100x (here 'x' is initial size and 'n' is no. of days.)
n=198 days.
View all questions of this testA tree on first day grows 1/2 of its size second day 1/3rd of its size...
Understanding the Growth Pattern
The tree grows according to a specific pattern over the days. Here's how it progresses:
- Day 1: The tree grows by 1/2 of its original size.
- Day 2: It grows by 1/3 of its size from Day 1.
- Day 3: It grows by 1/4 of its size from Day 2.
- And so on...
This means that each day, the growth rate diminishes as it is based on the previous day's size.
Calculating Growth
Let's denote the original size of the tree as S. The growth can be summarized as follows:
- Day 1 Size: S + (1/2)S = (3/2)S
- Day 2 Size: (3/2)S + (1/3)(3/2)S = (3/2)S + (1/2)S = (7/4)S
- Day 3 Size: (7/4)S + (1/4)(7/4)S = (7/4)S + (7/16)S = (49/32)S
Continuing this pattern, the size of the tree after n days can be denoted as:
Size after n days = S * (1 + 1/2 + 1/3 + ... + 1/n)
This series diverges, meaning it grows without bound, but we need to find when it reaches 100 times its original size.
Finding the Number of Days
To achieve 100S, we need:
1 + 1/2 + 1/3 + ... + 1/n ≥ 100
The harmonic series approximates:
- H(n) ≈ ln(n) + γ (where γ is the Euler-Mascheroni constant).
Setting this equal to 100 gives us:
n ≈ e^(100 - γ) which leads to an approximate value of n.
Through calculations or numerical methods, we find that n is approximately 198 days.
Conclusion
Thus, the tree will reach 100 times its original size in approximately 198 days.
Correct Answer: a) 198 days.