WHERE ARE ALL THE SMART MATH PEOPLE OMG

On average, how many more hits will he get when he bats 100 times at home during the day as opposed to 100 times away at night?

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)

Could somebody me with this radical simplification?