I assume that the figures you have given are AFTER the PA? Please make it clear in future.
NSI of £40,000: £37,700 x 20% £2,300 x 40%
SI of £5,700: £500 x 0% £5,200 x 40%
A word of advice – your basic knowledge on lots of areas seems to be weak. Instead of working through questions (which you don’t seem to be ready for), go back to your tuition materials to work on and strengthen your basic understanding.