I'm struggling hecking hard. Thanks for the help if possible <3

The marked price of an article is 25% above its selling price and the cost price is 30% less than its marked price . find the discount percent and gain percent. only a brainlest can solve it i will mark you brainlest

1) you deposit $2,500 in an account that earns 4% simple interest. how much do you earn in eight years?

How can you find the mean absolute deviation (mad) for this set of data?