Exams › SSC CGL (Prelims) › General

If x + 1/x = 6, find the value of 4x / (x^2 - 1).

1. sqrt(2)/2
2. 2*sqrt(2)/3
3. sqrt(3)/2
4. sqrt(2)/4

Correct answer: sqrt(2)/2

Solution

Dividing by x gives 4x/(x^2-1) = 4/(x - 1/x). Since (x - 1/x)^2 = 36 - 4 = 32, x - 1/x = 4*sqrt(2). Thus the expression = 4/(4*sqrt(2)) = 1/sqrt(2) = sqrt(2)/2.

Related SSC CGL (Prelims) General questions

• A shopkeeper sells rice at a discount of 6% on the marked price but uses a weight that is 25% less than the actual weight. Find his overall profit percentage.
• The profit made on an article sold for ₹2400 is equal to the loss incurred when it is sold for ₹2000. What will be the profit or loss percentage if the article is sold for ₹2200?
• Train A leaves Station X at 5:00 AM at 50 km/h. Train B leaves Station Y at 7:30 AM at 80 km/h. Both trains move towards each other. The distance between the stations is 500 km. When do they meet?
• A wholesaler marks up goods by 50% and gives a 12% trade discount. A retailer marks up by 20% and offers an 8% discount. The customer pays ₹12,216. What is the wholesaler's cost price approximately?
• If A : B = 3 : 4, B : C = 5 : 6, and C : D = 7 : 8, then find B : D.
• What is the result of $3^2 + 5 \div 0.8$?

⚔️ Practice SSC CGL (Prelims) General free + battle 1v1 →