The bell rings ; the first step you take is half the distance 'd' from your desk to the door. Each step you take is half the previous distance. How far have you traveled after your sixth step ?
we know that
step 1 -------> d/2
step 2 ------> d/4
step 3 ------> d/8
step 4 -----> d/16
step 5 -----> d/32
step 6 -----> d/64
In exponential notation
Let
y -----> the distance
x -----> number of step
so
y=d(1/2)^x
Verify
For x=1
y=d(1/2)^1=d/2
For x=2
y=d(1/2)^2=d/4
For x=6
y=d(1/2)^6=d/64
therefore
After the sixth step the total distance traveled is equal to
d/2+d/4+d/8+d/16+d/32+d/64
so
(d/64)(32+16+8+4+2+1)
(d/64)(63)
(63/64)d
or 0.98d