Percentage, Ratio & Average

What you'll learn

A from-scratch, exam-focused guide to percentage-fraction conversions, dividing in a ratio, and averages for RRB NTPC — with memory tables, fully worked examples, and speed shortcuts to grab easy Maths marks in the CBT.

This chapter has

Percentage, Ratio & Average — solved practice questions

8 Railways Mathematics questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   What is 25% of 480?

   • A100
   • B120
   • C96
   • D140
   Show answer & solution

   Correct answer: (B) 120

   25% = 1/4, so 480 ÷ 4 = 120.

2. Q2medium

   A number increased by 20% becomes 360. What was the original number?

   • A300
   • B320
   • C288
   • D340
   Show answer & solution

   Correct answer: (A) 300

   Original × 1.20 = 360, so original = 360 ÷ 1.2 = 300.

3. Q3easy

   Two numbers are in the ratio 3 : 4 and their sum is 560. What is the smaller number?

   • A320
   • B280
   • C240
   • D210
   Show answer & solution

   Correct answer: (C) 240

   Total parts = 3 + 4 = 7, one part = 560 ÷ 7 = 80, so smaller = 3 × 80 = 240.

4. Q4easy

   The average of 5 numbers is 27. What is their sum?

   • A125
   • B145
   • C150
   • D135
   Show answer & solution

   Correct answer: (D) 135

   Sum = average × count = 27 × 5 = 135.

5. Q5medium

   In an exam the pass mark is 40% of the total. A student needs 240 marks to pass. What is the maximum total marks?

   • A560
   • B600
   • C640
   • D500
   Show answer & solution

   Correct answer: (B) 600

   40% of total = 240, so total = 240 ÷ 0.40 = 600.

6. Q6medium

   What is the average of the first 10 even numbers (2, 4, ..., 20)?

   • A11
   • B10
   • C12
   • D9
   Show answer & solution

   Correct answer: (A) 11

   Their sum is 110 and there are 10 numbers, so the average is 110 ÷ 10 = 11.

7. Q7easy

   If 30% of a number is 90, what is the number?

   • A270
   • B330
   • C300
   • D360
   Show answer & solution

   Correct answer: (C) 300

   Number × 0.30 = 90, so number = 90 ÷ 0.30 = 300.

8. Q8medium

   Boys and girls in a class are in the ratio 5 : 3. If there are 240 students in total, how many are boys?

   • A90
   • B120
   • C160
   • D150
   Show answer & solution

   Correct answer: (D) 150

   Total parts = 8, one part = 240 ÷ 8 = 30, so boys = 5 × 30 = 150.

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