Explanation

The area of a rectangle is calculated by multiplying the length by the width:

Area=Length×Width

=7cm×2cm

=14 cm² 

Explanation

1. Let Ali's speed be x kmph. Then, the time taken by Ali to cover 30 km is 30/x hours.

2. Since Ali takes 2 hours more than Raza, the time taken by Raza to cover 30 km is (30/x) - 2 hours.

3. If Ali doubles his speed, his new speed is 2x kmph. The time taken by Ali to cover 30 km at this new speed is 30/(2x) hours.

4. According to the problem, if Ali doubles his speed, he would take 1 hour less than Raza. So, we can set up the equation:

(30/x) - 2 = (30/(2x)) - 1

Simplifying the equation, we get:

30/x - 2 = 15/x - 1

Multiplying both sides by x, we get:

30 - 2x = 15 - x

Simplifying further, we get:

x = 5

So, Ali's speed is 5 kmph.

Explanation

Let the speed of the train be x km/h and the speed of the car be y km/h.

Case 1: He travels 120 km by train and the rest (480 km) by car, taking 8 hours in total.

Time taken by train = Distance / Speed = 120 km / x km/h = 120/x hours

Time taken by car = Distance / Speed = 480 km / y km/h = 480/y hours

Total time = 8 hours = (120/x) + (480/y)

Case 2: He travels 200 km by train and the rest (400 km) by car, taking 8 hours 20 minutes (or 8.33 hours) in total.

Time taken by train = Distance / Speed = 200 km / x km/h = 200/x hours

Time taken by car = Distance / Speed = 400 km / y km/h = 400/y hours

Total time = 8.33 hours = (200/x) + (400/y)

Now, we have two equations and two variables. Solving them simultaneously, we get:

x = 60 km/h (speed of the train)

y = 80 km/h (speed of the car)

Explanation

Let's break down the problem to determine if the total time taken is indeed 5 1/2 hours.

Step 1: Determine how many forms are left after the first half-hour

Explanation

Explanation

To determine how many items the machine will produce in 10 minutes:

1. It takes 1/3 minute to produce one item.
2. In 1 minute, the machine produces 3 items (since 1 ÷ 1/3 = 3).
3. In 10 minutes, the machine will produce 3 × 10 = 30 items.

So, the machine will produce 30 items in 10 minutes.

Explanation

To find the number of dishes washed in 16 minutes, we need to calculate the rate of dishes washed per minute and then multiply it by 16.

Rate = 1350 dishes/hour ÷ 60 minutes/hour = 22.5 dishes/minute

Number of dishes washed in 16 minutes = 22.5 dishes/minute x 16 minutes = 360 dishes

So, the correct answer is: 360

Explanation

To solve the problem, follow these steps:

1: Determine B's efficiency compared to A:

• A can finish the work in 40 days, so A's work rate is  1/40 of the work per day.
  
• If B is 255% less efficient than A, it means B's efficiency is reduced by 255%, which implies B is not practically effective (usually considered inefficient or not working effectively in real terms).

2: Calculate B's efficiency:

• If B is 255% less efficient, B's effective efficiency would be negative, which isn't practically feasible. To make sense of this:
• Assume B’s efficiency is effectively lower compared to A in realistic scenarios.

3: Adjust B's effective efficiency for practical calculations:

• Let's use a model where B is significantly less efficient but not zero. For instance, if B’s efficiency is assumed to be around 10% of A’s for simplicity:
• B can do the work in approximately 400 days.

The closest feasible answer given practical scenarios and combined work rate calculations is None.

Explanation

Let's break this problem down step by step:

1. Let the distance between home and school be x km.
2. Time taken to go to school = Distance / Speed = x / 3
3. Time taken to return home = Distance / Speed = x / 2
4. Total time = 5 hours, so we can set up the equation: x / 3 + x / 2 = 5
5. To solve for x, we can find a common denominator (6) and add the fractions: (2x + 3x) / 6 = 5
6. Combine like terms: 5x / 6 = 5
7. Multiply both sides by 6 to eliminate the fraction: 5x = 30
8. Divide both sides by 5 to solve for x: x = 6

So, the correct answer is: 6 km

Explanation

Time = Distance / Speed

Time = 15 km / 80 kmph = 0.1875 hours

Multiply by 60 to convert to minutes:

0.1875 x 60 = 11.25 minutes

Now, find the time at 60 kmph:

Time = 15 km / 60 kmph = 0.25 hours

Multiply by 60 to convert to minutes:

0.25 x 60 = 15 minutes

Answer: 15 minutes