Two boats set off at the same time from one pier in the same direction. Their speeds are respectively equal to 20

Two boats set off at the same time from one pier in the same direction. Their speeds are respectively equal to 20 km / h and 30 km / h. What is the distance between them in 1 hour? In 1.5 hours? In how many hours the distance between them will be equal to 25 km ?

Number 1.

1. Let’s find what distance the 1st boat will pass in an hour.

20/1 = 20 kilometers.

2. Find the distance the second boat will travel in an hour.

30/1 = 30 kilometers.

3. Find the distance between the boats in an hour.

30 – 20 = 10 kilometers.

Number 2.

1. Let’s find what distance the 1st boat will pass in an hour and a half.

20/15 = 30 kilometers.

2. Find the distance the second boat will travel in an hour and a half.

30 / 1.5 = 45 kilometers.

3. Let’s find the distance between the boats in an hour and a half.

45 – 30 = 15 kilometers.

Number 3.

1. Let us take for a the time during which a distance of 25 kilograms is formed between the boats.

2. Let’s find, After how many hours the distance between them will be equal to 25 km

30 * a – 20 * a = 25 km;

10a = 25;

a = 2.5 hours.

Answer. In an hour there will be a distance of 10 kilometers between the boats, and 15 kilometers in an hour and a half. The distance between the boats will be 25 kilometers in 2.5 hours.