Given:
The function is:

To find:
The value of
.
Solution:
We have,

Putting
, we get



On combining like terms, we get


Therefore, the required function is
.
120 is the right answer that is what my teacher told me
First we convert it in seconds.
Number of seconds in 1 minute = 60 seconds
Therefore,
Number of seconds in 4.2 minutes = 4.2 x 60 = 252 seconds.
Next we convert it in hours.
60 minutes make up an hour. So we can write,
Number of hours in 60 minutes = 1 hour
Number of hours in 1 minute = 1/60 hour
Number of hours in 4.2 minutes = 1/60 x 4.2 = 0.07 hour
Therefore, the video is 252 seconds or 0.07 hour long.
56 dived by 2 equals 28. 28=green ribbon. Brown ribbon is 4 times as long. 28 times 4 equals 112. The brown ribbon is 112 cm long.