Answer: Let's first convert Cheryl's walking speed to meters per minute. Since she takes 80 steps per minute and each step is 81 cm, her walking speed is:
80 steps/min x 81 cm/step = 6480 cm/min
To convert this to meters per minute, we can divide by 100:
6480 cm/min ÷ 100 cm/m = 64.8 m/min
Now, let's find out the distance Cheryl walks to school. Since she walks for 12 minutes at a speed of 64.8 m/min, the distance she covers is:
distance = speed x time = 64.8 m/min x 12 min = 777.6 m
Next, let's find out how many steps Diane takes per minute on average:
90 steps/min
Since each of Diane's steps is 72 cm long, her walking speed is:
90 steps/min x 72 cm/step = 6480 cm/min
To convert this to meters per minute, we can divide by 100:
6480 cm/min ÷ 100 cm/m = 64.8 m/min
So Diane's walking speed is the same as Cheryl's. To find out how long it takes Diane to walk to school, we can use the formula:
distance = speed x time
Since Diane and Cheryl walked the same distance, we can use the distance we found for Cheryl:
777.6 m = 64.8 m/min x time
Simplifying this equation, we get:
time = 12 minutes
Therefore, Diane takes 12 minutes to walk to school.