How do you find the twenty-fourth positive multiple of 7?

The full question states: Find the twenty-fourth positive multiple of 7 and the sum of the first twenty-four positive multiples of 7.
I know how to find the sum of the first 24 positive multiples of 7 since its similar to this but how do I find the twenty-fourth positive multiple of 7?

1 Answer
Jul 15, 2018

#S=2100#

Explanation:

Remember what the multiples are:

The #1st# multiple of #7# is #1xx7 =7#
The #2nd# multiple of #7# is #2xx7 =14#
The #3rd# multiple of #7# is #3xx7 =21#

The #10th# multiple of #7# is #10xx7 =70# and so on.

The #24th# multiple of #7# is #24xx7 =168#

The sum of the first #24# multiples will be:

#S= 24/2(2(7)+23(7))#

#S=2100#

or using #T_24 =168#

#S = 24/2(7+168)#

#S=2100#