Answer :
We need to know about scientific notation to solve this problem. The number of seconds the playlist will play is 3.99 x 10^5.
Expressing a number in scientific notation means writing the number as a multiple of ten with ten raised to some power. We use scientific notation for numbers that are very small or very big. When writing numbers in scientific notation we always have one number other than zero before the decimal point. In this question we know that there are 1900 songs and each song has average time of 3.5 minutes, we need to convert the minutes into seconds and multiply the number of seconds of each song to 1900.
1 min=60 seconds
3.5 mins=3.5 x 60=210 seconds
210 x1900=399000 seconds
399000=3.99 x 10^5
Therefore the number of seconds that the playlist will play is 3.99x 10^5
Learn more about scientific notation here:
https://brainly.com/question/17581455
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