Mold grows on bread and every day it doubles by the eighth day the entire bread is covered with mold when was half the bread covered by mold

The mold will cover half the area as much are one day before it.

Step-by-step explanation:

Given:

Every day the mold on bread grows doubles

And by 8th day entire bread covered with it.

To Find:

When was half the bread covered by mold.

Solution:

It is said that area covered by mold doubles on each day

Total days taken to cover entire bread are 8

Let Area of bread be A

So Area covered (A) corresponds to 8 days with doubling.

So on previous day it should What ever area on 8th day/2

i.e A(8)/2

Similar on 6th day A(7)/2

So on 5ht day =A(6)/2 ,4th= A(5)/2,  on 3rd= A(4)/2, on 2nd=A(3)/2

On 1st =A(2)/2

So we required  Area= half of total.

One day before the 8th day will be 7th day

on that day it will cover half are so that on next day will cover the double of the previous area consumed.