Question

a cinema runs its movies in two different halls. one movie runs for 80 min. & second one runs for 120 min. both movies starts at 1:00 p.m. when will the movies begin again at same time?

Answer 1

this is the answer of your question

Answer 2

Answer:

The movies begin at the same time again at 5:00pm

Step-by-step explanation:

Given time of one movie = 80 min.

And the time of second one runs = 120 min.

Using prime factorization method,

 The prime factors of 80 are $\underline {2\times 2\times2\times2} \times5$  

 The prime factors of 120 are $2 \times 2 \times 2 \times\underline3 \times \underline5$

the least common multiple of 80 and 120 is

$=2\times 2\times2\times2\times3 \times5=240$

Since 240 is the time, it is  $240~minutes =\frac{240}{60} =4hours$

If the movies started at 1:00 p.m. then again after 4hours, that is at 5:00pm movies begin at the same time.

Therefore, the movies begin at the same time again at 5:00pm