Question

Два брата одновременно вышли из дома и направились в школу старший брат шел со скоростью 80 м в мин младший на 30 м в мин меньшей чем скорость старшего брата по этому он пришел в школу на 6 мин позже за сколько минут дошел до школы старший брат? Решите пжл

Answer 1

1) 80-30=50м/мин. - скорость младшего брата
х мин.- время, за которое до школы дошёл старший брат
(х+6) мин. - время, за которое дошёл младший брат
80х=50(х+6)
80х=50х+300
80х-50х=300
30х=300
х=10мин. - за столько минут старший брат дошёл до школы

Answer 2

Problem Analysis

To solve this problem, we need to find the time it took for the older brother to reach the school. We are given the speeds of both brothers and the time difference between their arrivals at the school.

Given Information

- Speed of the older brother: 80 m/min - Speed of the younger brother: 30 m/min less than the speed of the older brother - Time difference between their arrivals at the school: 6 minutes

Solution

Let's denote: - Speed of the older brother as S (given as 80 m/min) - Speed of the younger brother as S - 30 (30 m/min less than the speed of the older brother)

We can use the formula: time = distance/speed

Let's assume the distance to the school is D.

The time taken by the older brother to reach the school is D/S and the time taken by the younger brother is D/(S-30).

Given that the time difference between their arrivals at the school is 6 minutes, we can set up the equation: D/S - D/(S-30) = 6

We can solve this equation to find the value of D and then use it to find the time taken by the older brother to reach the school.

Calculation

Let's solve the equation D/S - D/(S-30) = 6 to find the value of D.

D/S - D/(S-30) = 6 D(1/S - 1/(S-30)) = 6 D = 6S(S-30)/(S(S-30))

Now, we can find the time taken by the older brother to reach the school using the formula time = distance/speed.

Time Taken by the Older Brother

Substitute the value of D and S to find the time taken by the older brother.

time = D/S time = (6S(S-30))/(S(S-30))

Let's calculate the time taken by the older brother.