Entrance Exams
Govt. Exams
Upstream speed = 48/4 = 12 km/h. Downstream speed = 56/4 = 14 km/h. Speed of current = (14-12)/2 = 1 km/h. [Note: If downstream is 60km instead, then current = (15-12)/2 = 1.5 ≈ 2]
Let initial salary = 100. After 15% increase = 115. After 10% decrease = 115 × 0.90 = 103.5. Net change = 3.5% increase
Relative speed = 45 + 55 = 100 km/h = 100 × 5/18 = 250/9 m/s ≈ 27.78 m/s. Distance = 27.78 × 8 ≈ 222m ≈ 220m
Combined rate = 1/15 + 1/20 - 1/30 = (4+3-2)/60 = 5/60 = 1/12. Time = 12 hours
If sum becomes 4 times, SI = 3P. SI = P×R×T/100 → 3P = P×R×15/100 → R = 20% p.a.
Let CP = 100. MP = 160. After 25% discount, SP = 160 × 0.75 = 120. Profit% = (120-100)/100 × 100 = 20%
CP per unit = 40/12 = 10/3. SP per unit = 1/5. Loss = (10/3 - 1/5)/(10/3) × 100 = 33.33%
Net rate = 1/12 - 1/15 = (5-4)/60 = 1/60. Time = 60 hours
Let amount at 5% = x. Then (x × 5 × 3)/100 + ((4000-x) × 7 × 3)/100 = 820. Solving: x = 2500
Relative speed = 60 + 40 = 100 km/h = 100 × 5/18 = 250/9 m/s. Total length = 250m. Time = 250/(250/9) = 9 seconds. But let me recalculate: 250 ÷ (250/9) = 9. Answer should be A, not D.