Math, asked by ash14774, 7 months ago

find the numbers of integers between 10 to 400 which are divisible by 3​

Answers

Answered by jaspalsingh1509
1

Answer:

187

Step-by-step explanation:

How many numbers between 1 and 400 are divisible by both 3 or 5?

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187

Lets understand it by taking a smaller range, say we have to find numbers between 1 and 20(both included) which are divisible either by 3 or by 5,

Here we can work it out normally this-

Numbers divisible by 3– 3 , 6 , 9 , 12 , 15 , 18

Numbers divisible by 5– 5 , 10 , 15 , 20

But here’s a catch,

the number 15, which is the LCM of 3 and 5, is in both the list, i.e., it is divisible by both 3 as well as 5 so we have to count it only once,

Numbers divisible by 15- 15

hence total numbers in this case=(Numbers divisible by 3)+(Numbers divisible by 5)-(Numbers divisible by the LCM of 3 and 5 ,i.e., 15 in this case)

=6+4–1

=9.

Now coming to the range of 1–400

Numbers divisible by 3-

First number is 3 and last number is 399, applying the formula of nth term of AP-

a+(n-1)d=Tn,where

a=First term , d=Common difference , Tn=nth term of AP , n=Number of terms

Here, a=3 , d=3 , Tn=399

So, 399 = 3+(n-1)3 or n = 133

Numbers divisible by 5-

First number is 5 and last number is 400,

So, a=5 , d=5, Tn=400

n can be obtained from 400= 5+(n-1)5 or n = 80

Numbers divisible by 15(LCM of 3 and 5)

First number is 15 and last number is 390,

So, a=15 , d=15, Tn=390

n can be obtained from 390 = 15+(n-1)15 or n = 26.

Thus , final answer=(Numbers divisible by 3)+(Numbers divisible by 5)-(Numbers divisible by the LCM of 3 and 5 ,i.e., 15 in this case)

=>133+80–26

=187

How many numbers between 1 and 400 are divisible by both 3 or 7?

How many numbers between 1 to 400 are exactly divisible by 7?

How many numbers between 1 and 400 are divisible by 4?

How many numbers between 1 and 600 are divisible by both 3 or 5?

What is the number of numbers between 100 to 400 that are divisible by either 2, 3, 5 and 7?

We have to calculate the numbers between 1 and 400 which are divisible by 3 or 5.

This means we have to count all the numbers which are either divisible by 3 or by 5 or by both.

Let us count individually each of the three cases

Case I: divisible by 3:-

3, 6, 9,…………, 399 are the numbers which are divisible by 3

Since this forms an AP with common difference 3

thereforeT(n)=a+(n−1)∗d

399=3+(n−1)∗3

396=(n−1)∗3

n−1=132...dividingbothsidesby3

n=133

hence 133 numbers are divisible by 3 between 1 and 400.

Case II: Divisible by 5:-

5, 10, 15, ………., 395 are the numbers which are divisible by 5.

T

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#include<studio.h>

int main()

{

int count = 0;

for(int i = 1; i < 401; i++)

{

if(i % 3 == 0 || i % 5 == 0)

{

count++;

}

}

printf(“%d”, count);

return 0;

}

This is a C program which gives the answer for your question. Copy the above code and paste it in the text editor in the following link:

First click on compile button then click on execute. The answer will be displayed in the green colored screen you see below.

Numbers upto 400 divisible by 3 or 5 = numbers divisible by 3 + numbers divisible by 5 - numbers divisible by 15

Numbers divisible by 3 = 399/3= 133

Numbers divisible by 5 = 400/5 = 80

Numbers divisible by 15 = 390/15=26

Answer is 133+80–26= 187

How many numbers between 200 and 300 are divisible by 3, 4, 5 together?

How many numbers from 1 to 400 are divisible by both 3 and 7 but not by 42?

How many numbers between 100 and 400 are divisible by 2, 3, 5 and 7?

How many digits in 1 to 500 are divisible by both 3 and 5?

How many numbers up to 2000 are divisible by both 5 and 9?

A no which is to be divisible by both 3 AND 5, which means it should be divisible by 15. So from 1 to 400,

400÷15 = 80/3 ,ie, 26 and 3/2

Which implies that there exist 26 nos which are divisible by 15, or by both 3 and 5.

Work the way you want from anywhere.

399=3+ 3(n1-1)

so n1=396/3 +1=133 nos divisible by 3.

395=5+5(n2-1)

so n2=79 nos divisible by 5

390=15+(n-1)15

I.e( 375/15)+1

so 26 numbers in total divisible by 15

so total nos = 133+79-26= 186 numbers

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