A book has 500 pages numbered 1,2,3 and so on. How many times does the digit 1 appear in the page numbers?
1 answer:
Answer:
Step-by-step explanation:
This book has 500 pages in total.
We should split up the place values.
1 - 9
One only appears once.
1
10 - 19
One appears 11 times.
1 + 11
20 - 99
One only appears 8 times.
1 + 11 + 8
Add:
1 + 11 + 8
=> 20
Since the same is for 200-299, and so on. Let us add twenty four times.
20 * 4
=> 80
Looking back to 100-199, there are 120 ones.
Add:
120 + 80
=> 200
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Answer:
9.694 years
Step-by-step explanation:
Let the investment is $P.
So, we are asked to determine the time it will grow to triple with the compound interest rate of 12%.
Let the time is y years.
So, from the formula of compound interest we can write
⇒
⇒
Now, taking log both sides we get,
y log 1.12 = log 3 {Since, }
⇒ 0.04922y = 0.477712
⇒ y = 9.694 years (Answer)