Question

В 9ч утра два катера отошли от пристани на озере в противоположных направлениях. В 9ч 30мин расстояние между ними было 39км 500м . С какой скоростью шёл первый катер, если скорость второго 45км/ч

Answer 1

S1-путь,пройденный 1 катером.S2-путь,пройденный 2 катеромS-расстояние м\у ними через 0,5часа.
S=S1+S2
S1=0.5·V1.S2=0.5·45=22.5(км)
S1=S-S2=39.5-22.5=17(км)
V1=S÷0.5=34()км\ч

Answer 2

Problem Analysis

We are given that two boats departed from a pier on a lake in opposite directions at 9:00 AM. At 9:30 AM, the distance between them was 39.5 km. We are also given that the second boat was traveling at a speed of 45 km/h. We need to find the speed of the first boat.

Solution

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

From 9:00 AM to 9:30 AM, which is a duration of 30 minutes, the second boat traveled a distance of 45 km/h * (30 minutes / 60 minutes) = 22.5 km.

At 9:30 AM, the distance between the two boats was 39.5 km. Since they were moving in opposite directions, the total distance covered by both boats is the sum of their individual distances.

So, the distance covered by the first boat is 39.5 km + 22.5 km = 62 km.

We can now use the formula: distance = speed * time to find the speed of the first boat.

62 km = x km/h * (30 minutes / 60 minutes)

Simplifying the equation, we get:

62 km = x km/h * 0.5 hours

Dividing both sides of the equation by 0.5 hours, we get:

x km/h = 62 km / 0.5 hours

Simplifying further, we find:

x km/h = 124 km/h

Therefore, the speed of the first boat is 124 km/h.

Answer

The first boat was traveling at a speed of 124 km/h.

Source:

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