Given the preimage and image, find the dilation scale factor

The holiday party will cost $160 if 8 people attend.if there are 40 people who attend the party, how much will the holiday party cost

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.

Me because i don't understand how to do it.: )