Question

Find the missing number.
12,15,9
17,21,13
___20,18​

Answer 1

$\LARGE{\bf{\underline{\underline{GIVEN\::-}}}}$

Find the missing number.

• 12,15,9

• 17,21,13

• _ 20,18

$\LARGE{\bf{\underline{\underline{TO\:FIND\::-}}}}$

• The Missing Number.

$\LARGE{\bf{\underline{\underline{SOLUTION\::-}}}}$

12, 15, 9

= 12 + 3

= 15 - 6 = 9

As 12 + 3 is 15 we should double the number and subtract the next number ( Applicable only the some kind of sums ).

_________

17, 21, 13

= 17 + 4 = 21

= 21 - 8 = 13

_________

__ 20, 18

= 19 + 1 = 20

= 20 - 2 = 18

So, Here we have to get the solution in the correct manner. That's why I subracted 20 - 18 to get 2, and did - 1 because it should be the greater number, This is also a method for doing these.

∴ 19, 20, 18