Question

Write which number in the given sequence replaces the question mark (?)

$21,24,30,33,39,42,48,51,57,?$

• A. $60$
• B. $63$
• C. $69$
• D. $71$

Answer 1

The correct option is A $60$

The given sequence follow a pattern :

$7\times 3=21$,

$8\times 3=24$,

$10\times 3=30$,

$11\times 3=33$,

$13\times 3=39$,

$14\times 3=42$,

$16\times 3=48$,

$17\times 3=51$,

$19\times 3=57$

Similarly, $20\times 3=60$.

Hence, $60$ replaces question mark.

(Alternate method)

$21+3=24$

$24+6=30$

$30+3=33$

$33+6=39$

$39+3=42$

$42+3=45$

$45+6=51$

$51+6=57$

And $57+3=60$