Question

Bonjour friends!

Chapter=>A.P


Solve this sum »»»


How many three digit numbers are divisible by 7?



Solve correctly.


The answer is 128.




:-)

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Answer 1

105, 112,........, 994

It forms an AP with first term 105 and common difference 7

let n be no of terms

an= a+ ( n-1)d

d= common term

an= n th term

a= first term

So

994 = 105 + ( n-1)7

994 = 105 + 7 n -7

994 = 98 + 7 n

7 n= 994 -98

7 n= 896

n= 128

Answer 2

Hey Mate!!

3 digit numbers divisible by 7 are

AP: 105,112,119.....994

a = 105

d = 7

an = 994

n =?

an = a+(n-1)d

994 = 105 + (n-1)7

889/7 = n-1

n = 127+1

n = 128

So, 128 three digit numbers are divisible by 7.

Hope it helps......