To find the expected number of supermarket shoppers who prefer plastic bags, you can use the given probability along with the total number of shoppers.
The probability of selecting a shopper who prefers plastic bags is 50%, or 0.5 in decimal form. Given that there are 150 shoppers, you can calculate the expected number of shoppers who prefer plastic bags as follows:
\[ \text{Expected number of shoppers} = \text{Total shoppers} \times \text{Probability} \]
\[ \text{Expected number of shoppers} = 150 \times 0.5 = 75 \]
Therefore, you can expect that 75 shoppers will prefer plastic bags.
The correct response is 75.