It took 32 minutes for Ella to go to school on Friday.
Step-by-step explanation:
Time for first four days in minutes,
30,28,34,31
Let x be the time on Friday
Average = 31 min
As we know
[tex]Average = \frac{Sum\ of\ term}{No.\ of\ terms}\\Average=\frac{30+28+34+31+x}{5}\\31=\frac{123+x}{5}[/tex]
Multiplying both sides by 5;
[tex]5*31=\frac{123+x}{5}*5\\155=123+x\\x+123=155\\x=155-123\\x=32[/tex]
It took 32 minutes for Ella to go to school on Friday.
Keywords: Average, Addition
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