Combined rate = 1/15 + 1/10 = 2/30 + 3/30 = 5/30 = 1/6. Time = 6 hours

Time = Distance/Speed = 300/60 = 5 hours

Speed of current = (Downstream speed - Upstream speed)/2 = (12 - 8)/2 = 2 km/h

SI = (5000 × 12 × 3)/100 = 1800. Amount = 5000 + 1800 = Rs. 6800

To solve percentage problems, we first find the original number, then calculate the required percentage of it.

Since 25% of the number equals 80, we set up an equation where the unknown number is x.

Now that we know the original number is 320, we find 60% of it.

The answer is (A) 192

Discount = 30% of 1000 = 300. Selling price = 1000 - 300 = Rs. 700

When a number undergoes multiple percentage changes, we must apply each change sequentially to find the net effect.

Step 1: Apply the 40% Increase

Starting with an original number, a 40% increase multiplies it by 1.40.

Step 2: Apply the 30% Decrease

A 30% decrease means we retain 70% of the value, so we multiply by 0.70.

Step 3: Calculate Net Change

The final value is 0.98x, which is 98% of the original value x.

The net change is a 2% decrease. Answer: (B)

To find the time saved, we need to calculate the original travel time and the new travel time after the speed increase, then find the difference.

Step 1: Calculate original travel time

Using the formula \(\text{Time} = \frac{\text{Distance}}{\text{Speed}}\):

Step 2: Find the new speed after 20% increase

A 20% increase means the new speed is:

Alternatively: \(\text{Speed}_{\text{new}} = 60 \times 1.20 = 72 \text{ km/h}\)

Step 3: Calculate new travel time at increased speed

Step 4: Find time saved

Converting \(\frac{1}{3}\) hour to minutes: \(\frac{1}{3} \times 60 = 20 \text{ minutes}\)

Therefore, time saved = 1 hour 20 minutes

Answer: 1 hour 20 minute (Option A)

SI = P × R × T / 100. 1200 = P × 8 × 3 / 100. P = (1200 × 100) / 24 = 5000.

A = P(1 + R/100)^T = 12000(1.1)^2 = 12000 × 1.21 = 14,520.