## OG 2020: Question No. 318

If x is an integer greater than 0, what is the remainder when x is divided by 4?

- The remainder is 3 when x + 1 is divided by 4.
- The remainder is 0 when 2x is divided by 4.

Source | OG 2020 |

Type | Data Sufficiency |

Topic | Number Properties |

Sub-Topic | Remainders |

Difficulty | Easy- Medium |

### Solution

__Steps 1 & 2: Understand Question and Draw Inferences__

__Steps 1 & 2: Understand Question and Draw Inferences__

In this question, we are given

- The number x is an integer, and x > 0

We need to determine

- The remainder, when x is divided by 4.

To find the remainder, when x is divided by 4, we need to know either the exact value of x, or the general expression expressing the number x.

As we do not have any information present in the question statement, let us now analyse the individual statements.

__Step 3: Analyse Statement 1__

__Step 3: Analyse Statement 1__

As per the information given in statement 1, when x + 1 is divided by 4, the remainder is 3.

- Hence, we can say x + 1 = 4 × k + 3, where k is a non-negative integer.
- x = 4 × k + 2
- By comparing the above equation with dividend = divisor × quotient + remainder, we can say that the remainder is 2.

Therefore, statement 1 is sufficient to answer the question.

__Step 4: Analyse Statement 2__

__Step 4: Analyse Statement 2__

As per the information given in statement 1, when 2x is divided by 4, the remainder is 0.

- Therefore, 2x is a multiple of 4.
- This can happen in two cases:
- When x is already a multiple of by 4
- x = 4 × k + 4 = 4(k + 1)
- Then 2x will also be divisible by 4.

- When x is not a multiple of 4 but x is a multiple of 2.
- Hence, x = 4 × k + 2 = 2(2k +1)
- And, 2x =4 (2k + 1) which makes 2x a multiple of 4.

- Hence, x = 4 × k + 2 = 2(2k +1)

- When x is already a multiple of by 4

Therefore, from this statement the remainder can be either 0 or 2.

Hence, statement 2 is not sufficient to answer the question.

__Step 5: Combine Both Statements Together (If Needed)__

__Step 5: Combine Both Statements Together (If Needed)__

Since we can determine the answer from statement 1 individually, this step is not required.

Hence, the correct answer choice is option A.

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