Missing DI — Study Notes for IBPS PO Prelims

Overview

Missing DI (Data Interpretation with missing values) is a hybrid question type that combines data interpretation with basic arithmetic reasoning. Instead of receiving a fully populated table, you are given a table where certain cells are blank. Your task is to first deduce the missing values using relationships provided in the question stem or embedded within the data itself, and then answer the questions.

This topic has become a staple in IBPS PO Prelims because it tests two skills simultaneously: your ability to extract hidden relationships (like row totals, column totals, or percentage linkages) and your speed in performing DI calculations. A typical set contains 5 questions worth 5 marks, making it a high-value target. Students who master the art of filling missing values quickly gain a significant time advantage over those who struggle with the setup phase.

The key to scoring well is recognizing that Missing DI is not harder than regular DI—it simply has an additional preliminary step. Once the table is complete, the questions themselves are standard: percentages, ratios, averages, and differences.

Key Concepts

• **Row and Column Totals**: Most missing DI tables provide totals. If a row has 4 values and a total, any one missing value equals Total minus the sum of known values.

• **Percentage Relationships**: Missing values are often described as "X is 20% more than Y" or "A constitutes 25% of total B." Convert these to equations immediately.

• **Ratio Clues**: Statements like "Male to Female ratio is 3:2" let you split a known total into parts. If total is 500, males = 300, females = 200.

• **Difference Clues**: "Production in March exceeds February by 150 units" gives you a direct equation: March = February + 150.

• **Dependent Cells**: Sometimes one missing value depends on another. Solve sequentially—find the independent variable first, then substitute.

• **Cross-Verification**: After filling all values, quickly check if row totals and column totals match the given figures. This catches calculation errors before you attempt questions.

• **Read All Clues First**: Before calculating anything, read every clue. Some clues only become usable after you've computed an intermediate value.

Formulas / Key Facts

| Relationship Type | Formula | |-------------------|---------| | X is P% more than Y | X = Y × (1 + P/100) | | X is P% less than Y | X = Y × (1 − P/100) | | X is P% of Y | X = Y × P/100 | | Ratio a:b with total T | First part = T × a/(a+b), Second part = T × b/(a+b) | | Average of n values = A | Sum of values = n × A | | If Total = Sum of parts | Missing part = Total − Sum of known parts |