Explanation

Total distance covered by both trains = 1160 + 1160 = 2320 meters

Time taken to cross each other = 20 seconds

Relative speed (combined speed of both trains) = Total distance / Time = 2320 / 20 = 116 meters/second

Since both trains have the same speed, the speed of each train = Relative speed / 2 = 116 / 2 = 58 meters/second

Convert meters/second to km/second: 58 / 1000 = 0.058 km/second (approximately)

Convert km/second to km/hour: 0.058 * 3600 = 208.8 km/hour

Explanation

Pipe A and pipe B can fill the tank in 3 hours and 5 hours, then total work = LCM of (3, 5) = 15 unit

Efficiency of pipe A = 15/3 = 5 unit and efficiency of pipe B = 15/5 = 3 unit

From 7 to 8 AM, pipe A alone done 5 unit, work remains (15 - 5) = 10 unit,

Now, pipe A and B together can do it in = 10/(5 + 3) = 10/8 hours = 10/8 × 60 = 75 min

 The required time is 8 AM + 75 min = 9 AM + 15 min = 9 : 15 AM

∴ The correct answer is 9 : 15 AM

Explanation

In the first y hours, the carpenter lays xy bricks.

In the 2y hours thereafter, he lays (x/2)(2y) = xy bricks.

Altogether, that's xy + xy = 2xy bricks.

Explanation

1. We are given that 1/2 inch is equal to 12 kilometers.

2. We want to find the distance in kilometers for 5-2/3 inches. First, let's convert the mixed number to an improper fraction:

5-2/3 = 17/3 inches

3. Now, let's set up a proportion using the given conversion factor:

(1/2 inch) / 12 km = (17/3 inches) / x km

4. We can then cross-multiply and solve for x:

(1/2) × x = (17/3) × 12
x = (17/3) × 12 / (1/2)
x = (17/3) × 24
x = 136 km
So, the distance in kilometers is 136 km.

Explanation

To find the number of lawns completed in 10 hours, we can set up a proportion:

2 hours / 3 lawns = 10 hours / x lawns

We can then cross-multiply and solve for x:

2x = 3 × 10

2x = 30

x = 30/2

x = 15

So, in 10 hours, 15 lawns will be completed.