Govt. Exams
Entrance Exams
Let initial salary = 100. After 15% increase = 115. After 10% decrease = 115 × 0.90 = 103.5. Net change = 3.5% increase
Let CP = 100. MP = 160. After 25% discount, SP = 160 × 0.75 = 120. Profit% = (120-100)/100 × 100 = 20%
SP = 500 × 1.24 = Rs. 620. Wait, let me recalculate: 500 + (500 × 0.24) = 500 + 120 = 620. Correct answer should be B.
When a boat moves in a river, its effective speed changes based on the stream direction. We use the formulas: Downstream speed = boat speed + stream speed, and Upstream speed = boat speed − stream speed.
Step 1: Calculate Downstream Speed
Downstream means the boat moves with the stream (both speeds add):
Step 2: Calculate Upstream Speed
Upstream means the boat moves against the stream (stream speed subtracts):
Step 3: Find the Ratio
The ratio of downstream to upstream speed is:
This simplifies to \(3:2\).
Answer: The ratio of downstream to upstream speed is \(3:2\) (Option B)
Speed in m/s = 72 × 5/18 = 20 m/s. Distance = 20 × 25 = 500 m
Combined rate = 1/24 + 1/36 = (3+2)/72 = 5/72. Time = 72/5 = 14.4 minutes
SI = (8000 × 12 × 1.5)/100 = 1440. Amount = 8000 + 1440 = Rs. 9440
Number = 180/0.45 = 400. So 80% of 400 = 320
Profit % = [(140 × 85)/100 - 100] = [119 - 100] = 19%
Boat speed = (Downstream + Upstream) / 2 = (20 + 12) / 2 = 32 / 2 = 16 km/h.
