Question

How many three digit numbers are divisible by 7
how to find the first digit

Answer 1

Answer:

This is an arithmetic progression

there are 128 three digit numbers divisible by 7

Step-by-step explanation:

We take 105 as our a in AP, since its the first three digit numbers divisible by 7

and 994 as our n th term since its the last three digit no. divisible by 7

while the difference d=7

now using the formula

Tn = a+(n-1)d

994=105+(n-1)7

994-105 = 7n-7

889+7 = 7n

896/7 = n

n=128