Punjab TET – Quantitative Aptitude
Topic: Tables
“Tables” in quantitative aptitude refer to pre‑computed lists that help you solve problems quickly.
They cover frequency, mean, weighted mean, rate‑time, interest, percentages, factorials, powers, etc.
For the Punjab TET exam, you’ll often be asked to interpret, fill in, or use these tables to compute missing values.
1. Simple Explanation
| Table Type | What it shows | Typical Use |
|---|---|---|
| Frequency Table | Number of occurrences of each value | Find mode, median, proportion |
| Mean Table | Sum and count of numbers | Compute average quickly |
| Weighted Mean Table | Weighted sum / total weight | Average of groups, weighted scores |
| Rate‑Time Table | Speed, distance, time relationships | Solve “speed‑distance‑time” problems |
| Interest Tables | Simple/compound interest, discount | Compute interest, maturity values |
| Percentage Table | Percentage values of a base | Quick 10%, 20%, 25% etc. |
| Factorial / Power Table | n!, n², n³, … | Compute large numbers quickly |
| Log / Exponential Table | Logarithms, eⁿ | Solve growth/decay problems |
Why use tables?
They save time, reduce arithmetic errors, and are ideal for mental math or when calculators are not allowed.
2. Key Points to Remember
| Topic | Key Idea | Formula / Shortcut |
|---|---|---|
| Frequency Table | Mode = value with highest frequency. Median = middle value (or average of two middle values). | For odd N: median = value at position (N+1)/2. For even N: average of values at positions N/2 and N/2+1. |
| Mean Table | Mean = (Sum of all numbers) / (Number of entries). | Use a pre‑tabulated "sum" column if available. |
| Weighted Mean Table | Weighted Mean = Σ(weight × value) / Σ(weight). | Multiply each value by its weight, sum, then divide by total weight. |
| Rate‑Time Table | Speed = Distance / Time. | Use a table of “Speed (km/h) = 60 km / 1 h = 60 km/h” etc. |
| Simple Interest Table | SI = P × R × T / 100. | Pre‑store 1%, 2%, …, 10% of each principal. |
| Compound Interest Table | CI = P × (1 + r/n)^(nT). | For yearly compounding, use (1 + r/100)^T. |
| Percentage Table | 10% of X = X/10. 20% = X/5. 25% = X/4. 33.33% ≈ X/3. | Memorize quick fractions. |
| Factorial Table | n! = n × (n-1) × … × 1. | Pre‑store 1! to 10! or 12! for quick lookup. |
| Power Table | n², n³, … | Pre‑store 1²–10², 1³–10³, etc. |
Tip: Always check if the table gives the exact value or an approximate one. If approximate, be ready to round or use the nearest value.
3. Worked Example
Problem
A teacher has 15 students. Their marks in a test are:
78, 82, 85, 78, 92, 85, 78, 90, 85, 78