Question

В лыжном кроссе участвовали 450 мальчиков и девочек. мальчики составляли 4/5(дробь) всех участников кросса. половина девочек и треть мальчиков сошли с дистанции. сколько лыжников прошло к финишу?

Answer 1

1) 450:5*4=360 мальчики
2) 450-360=90 девочек
3) 90:2=45 половина девочек
4) 360:3=120 треть мальчиков
5) 45+120=165 человек сошло с дистанции
6) 450-165=285 человек пришло к финишу
Ответ:285 человек

Answer 2

Calculation of the Number of Skiers Who Reached the Finish Line

To determine the number of skiers who reached the finish line, we need to calculate the number of boys and girls who completed the race.

Given: - Total number of participants: 450 (boys and girls) - Boys make up 4/5 (fraction) of all participants - Half of the girls and one-third of the boys did not finish the race

Let's break down the problem step by step:

1. Calculate the number of boys: - Boys make up 4/5 of all participants. - So, the number of boys is (4/5) * 450 = 360 boys.

2. Calculate the number of girls: - The remaining participants after accounting for the boys are the girls. - Total participants - Number of boys = Number of girls - 450 - 360 = 90 girls.

3. Calculate the number of boys who did not finish the race: - One-third of the boys did not finish the race. - So, the number of boys who did not finish = (1/3) * 360 = 120 boys.

4. Calculate the number of girls who did not finish the race: - Half of the girls did not finish the race. - So, the number of girls who did not finish = (1/2) * 90 = 45 girls.

5. Calculate the number of skiers who reached the finish line: - To find the number of skiers who reached the finish line, we subtract the number of boys and girls who did not finish from the total number of participants. - Number of skiers who reached the finish line = Total participants - (Number of boys who did not finish + Number of girls who did not finish) - Number of skiers who reached the finish line = 450 - (120 + 45) = 285 skiers.

Therefore, 285 skiers reached the finish line.