Question

Noah has $8$ toy cars and has a very clever way of naming them. He uses a different number for the different names of the cars as $3$ $6$ $9$ $12$ ____ $18$ ____ $24$. Find the names of the $5^{\text{th}}$ and $7^{\text{th}}$ car.

• A. $15,19$
• B. $15,21$
• C. $16,19$
• D. $16,22$

Answer 1

The correct option is B $15,21$

Given:

After observing the pattern in the sequence, we find:


$\therefore$ In the sequence, we need to add $3$ with previous number to get the next one.

Hence,
$\bullet$ the name of $5^{\text{th}}$ car
= name of $4^{\text{th}}$ car $+3$
$=12+3$
$=15$

$\bullet$ the name of $7^{\text{th}}$ car
= name of $6^{\text{th}}$ car $+3$
$=18+3$
$=21$