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ISRO Scientist CS 2014 Official Paper

Option 4 : 10^{3}

ISRO Scientist CS 2020 Official Paper

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80 Questions
240 Marks
90 Mins

The correct answer is **option 4.**

__Key Points__

**Binary Coded Decimal (BCD)** encoding scheme each of the decimal numbers (**0 - 9) **is represented by its equivalent binary pattern. Which is generally 4-bits.

**Step1: **A Switch can store **on** or **off **which means it takes one bit(0 for off, 1 for on) and each digit o**f BCD takes 4 bits.**

**Step2:** So there will be \(\frac{12}{4}\) = 3 BCD digits. A BCD digit can be from 0 to 9 which is total **10 possibilities.**

**Step3:** Therefore, diffrent possible BCD numbers in 12 switches are = **10 * 10 * 10 = 1000** = 103

**∴ Hence the correct answer is*** 103*.