Question

Электрическая плитка имеет две спирали. При включении одной из них вода закипит через 15 минут, второй - через 30. Найдите время, необходимое для закипания воды, если включить одновременно обе спирали параллельно.

Answer 1

Q=P1*t1=P2*t2=(P2+P2)*t
t=Q/(P2+P2)=Q/(Q/t1+Q/t2)=1/(1/t1+1/t2)=t1*t2/(t1+t2) = 15*30/(15+30) мин = 10 мин

Answer 2

Calculation of Water Boiling Time with Two Parallel Heating Elements

To find the time required for the water to boil when both heating elements are turned on simultaneously, we need to consider the individual boiling times of each heating element.

According to the information provided, one heating element takes 15 minutes to boil the water, while the other takes 30 minutes.

To determine the time required for both heating elements to boil the water, we need to find the least common multiple (LCM) of 15 and 30. The LCM is the smallest positive integer that is divisible by both numbers.

The LCM of 15 and 30 is 30 minutes. Therefore, it will take 30 minutes for both heating elements to boil the water when turned on simultaneously.

Answer: The time required for the water to boil when both heating elements are turned on simultaneously is 30 minutes.