Question

(a)
4 8 9
+ +
21 21 21​

Answer 1

Answer:

$4 + 8 + 9 + 21 + 21 = 63$

Answer 2

Step-by-step explanation:

The series is 2, 3, 4, 8, 9, 10, 20, 21, 22, …

If we observe the series,

First number + 1 = Second number (2 + 1 = 3)

Second number + 1 = Third number (3 + 1 = 4)

Third number × 2 = Fourth number (4 × 2 = 8)

Fourth number + 1 = Fifth number (8 + 1 = 9)

Fifth number + 1 = Sixth number (9 + 1 = 10)

Sixth number × 2 = Seventh number (10 × 2 = 20)

seventh number +1 = eighth number (20 + 1 = 21)

eight number +1 = ninth number (21 + 1 = 22)

We observe that in the first two resultant 1 is added to the previous number.

But in the third result, we have to multiply the previous number by 2, and again similar patterns we have to follow with the upcoming resultant.

Look at the series, we need to find the 10th number in it. Analyzing it we can infer that it will be obtained by multiplying the 9th number by 2.

So, ninth number × 2 = tenth number (22 × 2 = 44)