Question

от двух пристаней, находящихся на расстоянии 615 км, отплыли одновременно навстречу друг другу катер и моторная лодка.Встреча произошла через 15 часов . Катер шёл со скоростью 23 км/час . С какой скоростью шла моторная лодка?

Answer 1

За 15 часов катер прошёл 15*23 = 345 км. Значит, лодка прошла 615-345 = 270 км. Её скорость 270/15 = 18 км/ч.

Answer 2

1) 15*23=345 км прошел катер за 15 ч.

2) 615-345=270 км Расстояние, через которое катер встретился с моторной лодкой. 

3) 270:15=18 км.ч Скорость моторной лодки. 

Answer 3

Problem Analysis

We are given that a boat and a motorboat set sail simultaneously from two different piers that are 615 km apart. They meet each other after 15 hours. The speed of the boat is given as 23 km/h. We need to determine the speed of the motorboat.

Solution

Let's assume the speed of the motorboat is x km/h.

To solve this problem, we can use the formula: distance = speed × time.

The boat and the motorboat are traveling towards each other, so their combined distance is equal to the total distance between the piers, which is 615 km.

The boat travels for 15 hours at a speed of 23 km/h, so the distance it covers is: distance_boat = speed_boat × time = 23 km/h × 15 h = 345 km.

The motorboat also travels for 15 hours, but at an unknown speed x km/h. So the distance it covers is: distance_motorboat = speed_motorboat × time = x km/h × 15 h = 15x km.

Since the boat and the motorboat meet each other, their combined distance is equal to the total distance between the piers: distance_boat + distance_motorboat = 615 km.

Substituting the values we have: 345 km + 15x km = 615 km.

Now we can solve this equation to find the value of x.

Calculation

Let's solve the equation: 345 km + 15x km = 615 km.

Subtracting 345 km from both sides: 15x km = 615 km - 345 km.

Simplifying: 15x km = 270 km.

Dividing both sides by 15 km: x = 270 km / 15 km.

Calculating: x = 18 km/h.

Answer

Therefore, the motorboat was traveling at a speed of 18 km/h.

Verification

To verify our answer, let's substitute the value of x into the equation and check if it satisfies the given conditions.

The boat traveled for 15 hours at a speed of 23 km/h, so the distance it covered is: distance_boat = speed_boat × time = 23 km/h × 15 h = 345 km.

The motorboat traveled for 15 hours at a speed of 18 km/h, so the distance it covered is: distance_motorboat = speed_motorboat × time = 18 km/h × 15 h = 270 km.

The combined distance of the boat and the motorboat is: distance_boat + distance_motorboat = 345 km + 270 km = 615 km.

The combined distance is equal to the total distance between the piers, which confirms that our answer is correct.

Conclusion

The motorboat was traveling at a speed of 18 km/h.