What is the sum of the multiples of 3 between 100 and 1000

165150 is the sum of the multiples of 3 between 100 and 1000.

Step-by-step explanation:

We need to find the sum of multiples of 3 between 100 and 1000.

First we will find the Total number of multiples of 3 between 100 and 1000.

Let a be the first multiple and l be the last multiple of 3

100 is not the multiple of 3.

101 is not the multiple of 3.

102 is the multiple of 3.

Hence first term a = 102

Similarly.

1000 is not a multiple of 3

999 is a multiple of 3

hence last term l = 999

Also d is the common difference.

hence d = 3.

Now by using Arithmetic progression formula we get;

Hence there are 300 multiples of 3 between 100 and 1000

Now n=300, a=102, l = 999

Hence to find the sum of all the multiples we use the Sum of n terms in AP  formula;

Sum of n term

Hence,165150 is the sum of the multiples of 3 between 100 and 1000.

hreryryrranswer:

step-by-step explanation:

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)