Bpp practise kit ann, basil, chole

Ann is self employed
Taxable income for 16/17 was 76000
Ann made contribution 49,000 gross to personal contrib. Scheme between sept 16 and march 17
That was second year she had been a member and has unused annual allowance of 20,000 bf from 15/16

-whats ann income tax liability

The anawer is
81,000(32,000+49,000)x20%: 16200

I didnt get it.
I just extend the band to 81,000 so tax liab will be
76,000×20%= 15200

Could u explain it for me plz