Answer:
less value
Explanation:
To deterimine if value was improved or not, we need to compare the price reduction to the size reduction.
__
The reduction in price is ...
((new value)/(old value) -1) × 100%
= (42/50 -1) × 100% = -16%
The size reduction of 20% is more than the price reduction of 16%, so the chocolate bar is less value.
_____
Additional comment
Compared to the original value, the new price to chocolate ratio is ...
0.84/0.80 = 1.05
Effectively, the price was raised by 5%.