NECO Mathematics 2025 Past Questions.

Welcome to AllCBTs Mathematics Tutorial for NECO Mathematics 2025.
In this lesson, we’ll tackle frequently repeated NECO math questions, including mean and average scores, sector area, and other geometry concepts. Get your writing materials and calculator ready — let’s begin!

You can watch the full class in the video below:

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Question 1: Mean Score of Girls and Boys

Problem:
20 girls and Y boys sat for an examination. The mean score for the girls was 52, and for the boys, it was 57. If the total score for both girls and boys was 2750, find the number of boys Y.

Step-by-Step Solution:

Given:

• Mean score (girls) = 52
• Mean score (boys) = 57
• Total score = 2750
• Number of girls = 20

Step 1: Total score from the girls
Mean = Total Score ÷ Number of Students
So, Total Score (girls)=52×20=1040\text{Total Score (girls)} = 52 \times 20 = 1040Total Score (girls)=52×20=1040

Step 2: Score contributed by boys Total Score (boys)=2750−1040=1710\text{Total Score (boys)} = 2750 – 1040 = 1710Total Score (boys)=2750−1040=1710

Step 3: Let the number of boys be Y Mean (boys)=Total Score (boys)Y⇒57=1710Y⇒Y=171057=30\text{Mean (boys)} = \frac{\text{Total Score (boys)}}{Y} \Rightarrow 57 = \frac{1710}{Y} \Rightarrow Y = \frac{1710}{57} = 30Mean (boys)=YTotal Score (boys)​⇒57=Y1710​⇒Y=571710​=30

Final Answer: 30 boys
Option C

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Question 2: Finding the Area of a Remaining Sector

Problem:
A sector of angle 120° is cut out from a circle of radius 13.5 cm. What is the area of the remaining part of the circle?

Step-by-Step Solution:

Step 1: Understanding the Sector

• Total angle in a circle = 360°
• Removed sector = 120°
• Remaining (major sector) = 360° – 120° = 240°

Step 2: Area of a sector formula: Area=θ360×πr2\text{Area} = \frac{\theta}{360} \times \pi r^2Area=360θ​×πr2

Substitute values:

• θ=240\theta = 240θ=240
• r=13.5r = 13.5r=13.5
• π=227\pi = \frac{22}{7}π=722​

Area=240360×227×(13.5)2\text{Area} = \frac{240}{360} \times \frac{22}{7} \times (13.5)^2Area=360240​×722​×(13.5)2

Step 3: Simplify the expression:

• 240360=23\frac{240}{360} = \frac{2}{3}360240​=32​
• 13.52=182.2513.5^2 = 182.2513.52=182.25

Area=23×227×182.25\text{Area} = \frac{2}{3} \times \frac{22}{7} \times 182.25Area=32​×722​×182.25

Watch more educational videos and past questions: https://youtube.com/@allcbts

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Why These Questions Matter

These types of questions:

• Always appear in NECO, WAEC, and JAMB Mathematics papers
• Test your understanding of basic arithmetic, mean, and geometry
• Help build speed and accuracy with real-life math applications

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