Show that she takes between six and seven minutes to get to school.

Question

A child lives 200 metres from school. She walks 60 metres in the first minute and in each subsequent minute he walks 75%. lf the distance walked in the previous minute. Show that she takes between six and seven minutes to get to school.

Answer 1

You will need to know how far the student walked each minute.  You can do this by multiplying 60 - the number of meters covered in the first minute - by 0.75 raised to the number of minutes since the first minute.

Minute 1:  60 * (0.75)^0.  Any nonzero number raised to the 0 power = 1, so the child covered 60 m.

 

Minute 2:  60 * (0.75)^1 = 60 * 0.75 = 45 m.

 

Minute 3:  60 * (0.75)^2 = 60 * 0.5625 = 33.75 m.

 

Minute 4:  60 * (0.75)^3 = 25.31 m.

Minute 5:  60 * (0.75)^4 = 18.98 m.

 

Minute 6:  60 * (0.75)^5 = 14.24 m.

Minute 7:  60 * (0.75)^6 = 10.68 m.

 

Distance covered in first six minutes = 197.28 m.

Distance covered in first seven minutes = 207.96 m.

The child reached 200 m sometime during the seventh minute.