1/3 work in 5 days. Full work = 5 × 3 = 15 days

To find profit percentage, we track the price through markup and discount stages, then compare final selling price to cost price.

Step 1: Assume a Cost Price

Let Cost Price = \(\text{₹}100\) (assume convenient value)

Step 2: Calculate Marked Price (25% markup)

The shopkeeper marks goods 25% above cost price:

Step 3: Calculate Selling Price (after 10% discount)

A discount of 10% is given on the marked price:

Step 4: Calculate Profit Percentage

Profit = Selling Price − Cost Price:

Profit percentage:

Answer: The shopkeeper makes a profit of \(12.5\%\) (Option A)

A's rate = 1/12, B's rate = 1/18. Combined rate = 1/12 + 1/18 = 5/36. Time = 36/5 = 7.2 hours

To find the speed of the boat in still water, we use the relationship between upstream/downstream speeds and the boat's speed relative to water.

Step 1: Find upstream and downstream speeds

Upstream speed is distance divided by time:

Downstream speed:

Step 2: Set up equations using boat and current speeds

Let \(b\) = speed of boat in still water and \(c\) = speed of current.

When going upstream, the current opposes motion:

When going downstream, the current aids motion:

Step 3: Solve for boat speed

Add equations (1) and (2) to eliminate \(c\):

Answer: The speed of the boat in still water is \(5.5\,\text{km/h}\) (Option A)

To find the final amount with compound interest, use the formula \(A = P(1 + r)^n\) where principal is compounded annually.

Step 1: Identify the given values

Step 2: Apply the compound interest formula

The amount after compound interest is:

Step 3: Substitute the values

Step 4: Calculate the final amount

Answer: The amount is Rs. 5832 (Option A)

Speed = Distance/Time = 160/8 = 20 m/s = 20 × 3.6 = 72 km/h

Combined rate = 1/15 + 1/20 = 7/60. Time = 60/7 ≈ 8.57 days

SP = CP × (1 - loss%) = 8000 × 0.85 = Rs. 6800

Relative speed = 80 - 60 = 20 km/h. Distance = 20 × 3 = 60 km

If boys:girls = 3:2 and boys = 15, then girls = (2/3) × 15 = 10