Question

8. How many 3-digit numbers are divisible by 7?​

Answer 1

Answer:

(128) 3-digit are dibisble by 7

Answer 2

Answer:

128, three-digit numbers are divisible by 7

Step-by-step explanation:

Numbers divisible by 7:

7,14,21...70..77..105 .. 994.

So, here, the first three digit number divisible by 7 is 105.

and last three digit number divisible by 7 is 994.

we can write the series as:

105 , 112,119 ..., 994

comm0n difference = 119 - 112 = 112- 105 = 7

It means the given series is in A.P with first term as 105.

General formula for finding number of terms in an AP is given as:

Tn = a + (n - 1) d

994 = 105 + (n-1)*7

994 = 105 + 7n - 7

896 = 7n

or, n = 896/7

or, n = 128

Therefore, 128, three-digit numbers are divisible by 7