bpp mcq bank 34

hello
i have a doubt

non savings income – 1000
savings income- 5500
what is income tax liability?

answer:
500

1000*20/100 200
(5000-1000)=4000*0 0
(5500-4000) 1500*20/100 300
tax liability =500

sir can you please explain why they have deducted 1000?

is it because teh rule says that 0% applies to savings incoe where it falls within first 5000 of taxable income?

for my solution
i did like this
1000*20/100
5000*0/100
500*10/100
which is wrong

so my doubt is why they are deducting 1000