Answer:
Her usual time from home to school is 30 minutes
Step-by-step explanation:
At any point in time;
distance = speed * time
Here, we want to calculate the normal time she spent going from home to school
Let the normal time be x minutes
And the normal speed be t m/min
Today, she increased her speed by 20%
Her speed today will be t + 20/100 * t =
1.2t m/min
Her distance from how to school normally is
xt meters
Now what this means is that, at the increased speed, she was able to get to school 5 minutes earlier
What we are saying is although, she lost 20 minutes initially, she was able to beat down the lateness by 5 minutes
So, the time spent on her increased speed journey is;
(x-5) minutes
At any point in time, the distance will be equal;
Thus, mathematically;
xt = 1.2t(x-5)
xt = 1.2xt - 6t
6t = 1.2xt-xt
6t = 0.2xt
t cancels out
0.2x = 6
x = 6/0.2
x = 30 minutes
