Personal Tax - HELP

I am really struggling on FA14.
I just cannot figure out how they have got the figures in the last column???

Source of investment income Investment income received Other taxable income Taxable investment income Additional tax
ISA 240 42000 0 0

Building society 1840 30000 2300 87


Dividens 846 74500 960 216

Can anyone explain this to me??
I just cannot figure out how they have got the figures in the last column???

Source of investment income Investment income received Other taxable income Taxable investment income Additional tax
ISA 240 42000 0 0

Building society 1840 30000 2300 87


Dividens 846 74500 960 216

Can anyone explain this to me??
0
Comments
firstintuition.co.uk/
Building society interest + other taxable income = £32,300. £435 is taxed at 40% so £174. Minus 20% taxed at source (£87) = additional tax to pay £87
Dividend is taxed entirely at higher rate of 32.5% so £312 minus 10% taxed at source (£96) = £216 additional tax