Gordon owns a shop.

here are the prices of three items in gordon's shop and in a supermarket.

gordon's shop

400g loaf of bread £1.22
1 litre of milk £0.96
40 tea bags £2.42

supermarket

400g loaf of bread £1.15
1 litre of milk £0.86
40 tea bags £2.28

gordon reduces his prices by 5%
will the total cost of these three items be cheaper in gordon's shop than in the supermarket?

show all working out, very much appreciated!

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.