Answer:
There are 142 whole numbers less than 1000 and divisible by 7.
Explanation:
The multiples of 7 form an arithmetic sequence like shown:
7, 14, 21, ...
The last term of this sequence can be found by dividing 1000/7=142.9 and rounding down to the previous integer: 142*7= 994.
Thus, the sequence has:
a1=7, r=7, an=994. We need to find n and we'll do that by using the general term formula:
![a_n=a_1+(n-1).r](https://img.qammunity.org/2021/formulas/mathematics/high-school/36rka38jdixrtxea86wjwdj963b9hpidcv.png)
And solving for n:
![\displaystyle n= (a_n-a_1)/(r)+1](https://img.qammunity.org/2021/formulas/mathematics/high-school/b3o3qr7wdz4uhnfzs3azsyr0yckpoev2wc.png)
![\displaystyle n= (994-7)/(7)+1](https://img.qammunity.org/2021/formulas/mathematics/high-school/tfplv5dqr5jfshk1j187jfbpchwhtw2e2b.png)
n = 142
There are 142 whole numbers less than 1000 and divisible by 7.