Question

В школе нужно покрасить 180 дверей.один маляр покрасит все двери за 15 дней,а другой за 10 дней.за сколько дней они покрасят все двери работая вместе?

Answer 1

1) 180/15=12дв 1-й рабочий за 1 день
2) 180/10=18дв 2- й рабочий за 1 день
3) 12+18=30дв два рабочих за один день
4) 180/30=6дв вместе

Answer 2

Calculating the Time to Paint 180 Doors

To find out how long it will take for two painters to paint 180 doors working together, we can use the concept of "work done per unit time."

Let's denote: - The number of days it takes for the first painter to paint all the doors as D1 = 15 days. - The number of days it takes for the second painter to paint all the doors as D2 = 10 days. - The total number of doors to be painted as N = 180 doors.

The formula to calculate the time it takes for two workers to complete a task working together is: 1 / (1/D1 + 1/D2)

Calculation

Using the formula: 1 / (1/15 + 1/10) = 1 / (2/30 + 3/30) = 1 / (5/30) = 30/5 = 6 days

Therefore, working together, the two painters will paint all 180 doors in 6 days.

This calculation is based on the concept of work done per unit time and the assumption that the painters work at a constant rate.