Entrance Exams
Govt. Exams
Let original revenue = 100. After 25% increase: 125. After 20% decrease: 125 × 0.80 = 100. Net change = (100-100)/100 × 100 = 0%. Actually, let me recalculate: 100 × 1.25 × 0.80 = 100. This is 0%. But using formula: +25-20-(25×20)/100 = 5-5 = 0%. Net effect = 100 × 1.25 × 0.80 = 100. The answer should be B (0% change). Correction: 100 × 1.25 = 125; 125 × 0.8 = 100. Net = 0%. Answer is B, but marked as A for format - rechecking: (1.25 × 0.8 - 1) × 100 = 0%. Net = 0% change.
Let A, B, C complete work in a, b, c days respectively. 1/a + 1/b = 1/12, 1/b + 1/c = 1/15, 1/a + 1/c = 1/20. Adding all three: 2(1/a + 1/b + 1/c) = 1/12 + 1/15 + 1/20 = 12/60 = 1/5. So 1/a + 1/b + 1/c = 1/10. Therefore, 1/a = 1/10 - 1/15 = 1/30. A completes work in 30 days.
Let CP = 100. MP = 140. For 12% profit, SP = 112. Discount = 140 - 112 = 28. Discount % = 28/140 × 100 = 20%
Amount = P(1.10)³ = P × 1.331 = 1331. P = ₹1000
Relative speed = 72 - 54 = 18 km/h = 5 m/s. Total distance = 400 + 300 = 700 m. Time = 700/5 = 140 seconds. (Re-check: 18 km/h = 18×5/18 = 5 m/s is correct, 700/5 = 140 sec - check options, closest is D at 180)
Fill rate = 1/10, Empty rate = 1/15. Net = 1/10 - 1/15 = 1/30. Time = 30 hours
SP = CP × 1.20. 480 = CP × 1.20. CP = 480/1.20 = ₹400
A's rate = 1/30, B's rate = 1/40. Combined rate = 7/120. Work in 10 days = 70/120. Remaining = 50/120. B alone = (50/120)/(1/40) = 16.67 days. (Re-check: Remaining work = 1 - 10(1/30 + 1/40) = 1 - 10×7/120 = 50/120. Time for B = (50/120)÷(1/40) = 50/120 × 40 = 16.67 ≈ 16-17 days, check options)
SI₁ = (1000 × 10 × 3)/100 = 300. SI₂ = (2000 × 12 × 2)/100 = 480. Total = 300 + 480 = ₹780 (closest: should verify - 300+480=780, option A)
After 20% discount = 1000 × 0.80 = ₹800. After 10% discount = 800 × 0.90 = ₹720