From two settlements, the distance between which is 21 km, at the same time brother and sister came

| May 10, 2021 | education

From two settlements, the distance between which is 21 km, at the same time brother and sister came out to meet each other. When they met, it turned out that the brother walked in one whole one-fourth (fraction) times more distance than the sister. How many hours after the exit did they meet, if the brother’s speed is 5 km / h?

If a brother has traveled 1 1/4 times the distance than his sister, then his speed is greater than that of his sister, and his sister’s speed is 1 1/4 times less than that of his brother. Having found the speed of the sister, we find the speed of convergence and the time after which the brother and sister met:

1) What is your sister’s speed?

5: 1 1/4 = 5: 5/4 = 5 * 4/5 = 4 (km / h) sister’s speed.

2) What is the speed of convergence?

5 + 4 = 9 (km / h) approach speed.

3) How many hours after leaving did they meet?

21: 9 = 2 1/3 (h).

Answer: 2 hours and 20 minutes after the release, the brother and sister met.



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