8000 blood donors were registered with a Samarpan Blood Bank.Some student organizations started mobilising people for this noble cause..As a result,the no. of donors registered increased at the rate of 20% per half year..FInd the no. of new registrants during 1 1/2 years.

Total number of blood donors registered = 8000
Rate of increasing number of donors per half year = 20%
So, number of new registrants after 6 months = $8000\times \frac{20}{100} = 1600$
So total number of registrants after 6 months = 8000 + 1600 = 9600
Then number of new registrants after one year = $1600+9600\times \frac{20}{100} = 1600+1920 = 3520$
So total number of registrants after one year = 8000 + 3520 = 11520
Then number of new registrants after one half year = $3520+11520\times \frac{20}{100} = 3520+2304 = 5824$