Sequence Solution: 20 : 11 :: 102 : ?

Step 1: Find the Relationship Between 20 and 11

When looking at 20 and 11, we notice that 11 is obtained by subtracting 9 from 20. Mathematically:

20 - 9 = 11

So, the rule for this sequence might involve subtracting 9.

Step 2: Apply the Same Rule to 102

Using the same rule, subtract 9 from 102:

102 - 9 = 93

But this doesn't match any option in the choices given. This means there may be another pattern involved.

Step 3: Check Another Possible Pattern

Instead of subtracting, let’s try dividing. For 20 : 11, if we divide 20 by 2, the result is 10, and adding 1 gives us 11. Mathematically:

(20 ÷ 2) + 1 = 11

Now, apply the same rule to 102:

(102 ÷ 2) + 1 = 51 + 1 = 52

Step 4: Match the Answer

From our calculation, the missing number is 52, which matches option b.

Final Answer:

The missing number in the sequence 20 : 11 :: 102 : ? is 52.