Chem question help pls

Hi, there are 2 chiral carbons which can be arranged in total 4 different ways
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-+
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and for each of the 4 arrangements the double bond can be either E or Z 4x2=8
hope this helps

Hi,
Please could I have help on part ii. I know there are two chiral carbons and one double bond so I thought there will be 6 isomers, how did they get 8?
Question: https://ibb.co/3yP94Q6D
Thanks!

The general rule of thumb is that when you have n stereogenic centres (e.g chiral carbons and asymmetrical alkenes), the maximum number of stereoisomers possible is 2^n.
Since n = 3, there are 2^3 = 8 stereoisomers.
This can be derived from probabilities you did in GCSE/equivalent level maths. The proof likely isn’t needed and I’d say the above explanation is perhaps more likely to be what an examiner would expect.