Question

What's the rule for the given sequence of numbers if $n$ indicates ${}^{\prime }{n}^{\prime }$th number?
5, 10, 15, 20.....

• A. $5n$
• B. $15n$
• C. $10n$
• D. $3n$

Answer 1

The correct option is A $5n$

In the given sequence of numbers,

1st number = 5 = $5\times 1$
2nd number = 10 = $5\times 2$
3rd number = 15 = $5\times 3$
4th number = 20 = $5\times 4$
. .
. .
. .
. .
$n$th number = $5\times n$
= $5n$

$\therefore$ The rule for the given sequence is $5n$.