Answer:
21 minutes
Step-by-step explanation:
I'll show you two way of solving:
1) Using division and multiplication with the given information
We can find out how many times 210 minutes is more than 30 minutes.
210/30 = 7
210 minutes is 7 times 30 minutes.
If for 30 minutes of music it needs 3 minutes of commercials, then for 7 times as much music played it needs 7 times the time of commercials.
7 * 3 minutes = 21 minutes
Answer: 21 minutes
2) Proportion
3 minutes of commercials is to 30 minute of music as x minutes of commercials is to 210 minutes of music
3/30 = x/210
Cross multiply.
30x = 3 * 210
Divide both sides by 30.
x = 3 * 210/7
x = 3 * 7
x = 21
Answer: 21 minutes
