Question

Find the next term in the sequence given below:
$1$ $3$ $6$ $10$ $15$

• A. $18$
• B. $19$
• C. $20$
• D. $21$

Answer 1

The correct option is D $21$

Given sequence: $1$ $3$ $6$ $10$ $15$


By observing the pattern in the sequence​​​​​, we get:


$2$nd term $=1$st term $+2$
$3$rd term $=2$nd term $+3$
$4$th term $=3$rd term $+4$
$5$th term $=4$th term $+5$

$\therefore 6^{\text{th}}\text{term}=5$th term $+6=15+6=21$


Therefore, the $6$th term in the sequence $1$ $3$ $6$ $10$ $15$ is $\underset{–}{21}$.​​