Percentages | General Aptitude for GATE PSU ESE AE/JE

Percentages are one of the most important topics in General Aptitude for exams like GATE, PSU, ESE, AE/JE. A strong understanding of percentages helps in solving questions from profit & loss, ratio, data interpretation, and more.

What is Percentage?

Percentage means "per hundred". It is represented by the symbol %.

Formula:
Percentage = (Value / Total Value) × 100

Example:

If a student scores 45 out of 60:
Percentage = (45/60) × 100 = 75%

Important Percentage Formulas

• x% = x/100
• Increase: New Value = Original Value × (1 + x/100)
• Decrease: New Value = Original Value × (1 − x/100)
• Successive Change: Net % Change = a + b + (ab/100)

Important Percentage Tricks

• 50% = 1/2
• 25% = 1/4
• 20% = 1/5
• 10% = 1/10
• 1% = Divide by 100

Questions on Percentages

Question 1

A number is increased by 20% and then decreased by 20%. What is the net change?

Solution:
Net Change = 20 − 20 − (20×20)/100 = −4%
Answer: 4% decrease

Question 2

If the price of a product increases by 25%, by what percentage should consumption be reduced to keep expenditure constant?

Solution:
Required reduction = [x / (100 + x)] × 100
= (25 / 125) × 100 = 20%
Answer: 20% decrease

Question 3

In an exam, 60% students passed. If 240 students passed, find total number of students.

Solution:
60% = 240
Total = 240 × (100/60) = 400
Answer: 400 students

Common Mistakes to Avoid

• Confusing percentage increase and decrease
• Ignoring base value change
• Not using shortcut formulas

Exam Tips

• Memorize fraction to percentage conversions
• Use shortcut formulas for faster calculation
• Practice previous year questions regularly

📢 GATE 2027/28 | ARJUNA Batch – Engineering Maths & General Aptitude

Prepare Engineering Mathematics & General Aptitude for GATE PSU & ESE with Priyanka Sharma Ma’am (15+ Years of Teaching Experience) at Studify+.

🎯 ARJUNA Batch Highlights:

• ✔ Complete Engineering Mathematics coverage
• ✔ Complete General Aptitude preparation
• ✔ Live + Recorded Classes
• ✔ Concept clarity + practice questions
• ✔ 30 Years GATE PYQs – All Branches
• ✔ Chapter Tests / Subject Tests
• ✔ Designed for All GATE Branches

📚 Branches Covered:

ME | CE | EC | CS | EE | IN | MN | PE | XE | CH | PI | TF | AE | AG | GE & All

🚀 Start your GATE preparation with expert guidance today!

🔗 Explore Courses:
https://www.studifyplus.com/s/store

📱 Download Our App:
https://rb.gy/a3lwgu

📞 For More Details:
WhatsApp / Call: 8200789441

✨ Build strong fundamentals in Maths & Aptitude and boost your GATE score!