Question

Первая бригада может отремонтировать дорогу за 90 дней,а вторая - за 45 дней.За сколько дней будет закончен ремонт этой дороги, если обе бригады будут работать совместно?

Answer 1

ОДНА ОТРЕМАНТИРУЕТ 1 90ТУЮ ЗА ДЕНЬ ДРУГАЯ 1 45УЮ ВМЕСТЕ     3 90ЫХ ЗА ДЕНЬ 90:3=30 ДНЕЙ ЭТО ОТВЕТ

Answer 2

Calculation of Road Repair Time

To determine how long it will take to complete the road repair when both the first and second brigades work together, we need to calculate their combined efficiency.

Let's denote the time taken by the first brigade to repair the road as T1 (90 days) and the time taken by the second brigade as T2 (45 days).

The formula to calculate the combined efficiency is as follows:

Combined Efficiency = (T1 * T2) / (T1 + T2)

Substituting the given values, we have:

Combined Efficiency = (90 * 45) / (90 + 45)

Simplifying the equation:

Combined Efficiency = 4050 / 135

Combined Efficiency = 30

Therefore, the combined efficiency of both brigades working together is 30.

To calculate the time it will take for both brigades to complete the road repair, we can use the formula:

Total Time = (T1 * T2) / (T1 + T2)

Substituting the given values:

Total Time = (90 * 45) / (90 + 45)

Simplifying the equation:

Total Time = 4050 / 135

Total Time = 30

Therefore, it will take both brigades working together a total of 30 days to complete the road repair.

Please note that the above calculation assumes that both brigades work at a constant rate and there are no other factors that may affect the repair time.