Dice Concepts for Railway Exams (NTPC, Group D, RPF)

• The class focuses on preparing students for railway exams like NTPC, Group D, and RPF, where questions from the डाइस (Dice)topic are highly expected.
• The class emphasizes clearing the concepts of dice and ensuring selection in the exams.

Basic Concepts of Dice

• The class starts with the basic definitions of "साधारण पासा" (Ordinary Dice) and "मानक पासा" (Standard Dice).
• मानक पासा (Standard Dice): It is a dice where the sum of any two visible faces is not equal to 7. It remains constant and does not change.
• साधारण पासा (Ordinary Dice): When any two visible faces of a dice add up to 7, it is referred to as साधारण पासा (Ordinary Dice).
• Determining पासा type: it will determine the approach for solving questions, distinguishing between standard and ordinary dice is important.

Identifying Dice

• In an ordinary dice, the sum of two surfaces is seven.
• In a standard dice, the sum of two surfaces is NOT seven.

Question Types

• Questions will always ask for the opposite surface in the dice
  • In English, it is called Opposite Surface
• The opposite surface is also called विपरीत सतह in Hindi.
• The following types of questions can be asked:
  • Single dice
  • Double dice
  • Double dice with more than two dice
  • Open dice

Solving Questions with Single Dice

• The first step involved to solve single dice questions is to identify whether the dice is मानक पासा or साधारण पासा

Standard Dice - Trick to find opposite surface

• The trick to find the opposite surface is to find out the number that, when added to the given surface, gives the sum of 7.
• The following must be done:
  • The questions must give you a single dice
  • You must first check, is the dice, मानक पासा?

Ordinary Dice - When the opposite can't be found directly

• When two surfaces sum to 7: it means the dice is ordinary.
• The answer is "कैन नॉट डिटरमाइंड" (cannot determine) and "डिपेंड्स ON OPTION" (depends on the options).
• You can also say that the answer will be among the numbers not visible on the dice
• Since the answer depends on the option, the answer will always be among the digits not on shown on the dice face

When Options Have Simbols, Letters or Colours

• For the following questions, the answer depends on the options.
  • colour questions
  • symbol questions
  • Letter questions

Solving Double Dice Questions

• There are two concepts that apply to solving double dice questions, if understood, you can solve any question.
• To solve double Dice questions:
  • Find the repeating, common number from both faces
  • Write the repeating number below each other
  • Rotate each dice face clockwise
  • The number below each other will be the opposite

Note when the opposite is NOT visible

• The following will happen:
  • Find the numbers that are repeating on both dice faces
  • Since we know that there can only be 6 digits on one dice, find the missing digit
  • The missing digit will be the opposite, because it cannot be on the face
  • The number you are trying to find the opposite of, cannot be the opposite of ITSELF

Trick: When the Dice Have A Common Number, At the SAME Spot

• When the dice have are the same, in the same spot, it means:
  • The opposite faces are facing each other
  • The opposite surfaces will be in the same spot too
  • Making it very easy to find the opposite, instantly

When Two Surfaces are the same

• The logic is to:
  • identify the two common surfaces on both dice
  • the remaining surface will be the answer
  • then, both surfaces are the opposite

When Two Surfaces are the same - What is the opposite surface on the common digits?

• The answer is:
  • It depends on the options!
  • However, it will be the number NOT visible on BOTH dices!

Three or Four Dice Faces

• When you are given dices with 3 or more faces, you must apply the "two surface common rule".
• If there are two surface that are the same, at the same spot, immediately, you can identify the opposites
• Otherwise, use the clock-wise rotation strategy
• If that does not work, you can find which surface are missing from the list of surfaces, then identify the missing digit

Strategy for "orally" and easily solving dice questions

• For number based dices: you must know, there can be only 6 digits on a single dice
• Identify common numbers on the dice: the opposite must be a missing
• Therefore if you can only see the numbers: 1,2,3,4, and 5: you know "6" will be the opposite

Rules for Open Dice

• Opposite surfaces are always alternate
• Alternate: means "leaving one surface, then the opposite"
• Imagine the dice in 2-D, therefore only two directions, therefore easily to identify

Solving "Open Dice" faces being combined and rolled

• The opposite surfaces are faces that CANNOT be beside each other
• Two opposite surfaces can never be together
• You can consider them "married couple" or "partners"
  • They must never be seen beside eath other
• If they are, the answer is WRONG!
• Therefore to solve:
  • First identify the partners on an "open dice" setup
  • Find the partners that are beside each other, on the answer, and exclude!