Friend needs help but my brain isn't working at the moment. What's the answer?

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 (%)

Lucy and donavan measured the length of the school garden. lucys measurement is 11.3m and donavans measurement is 113 cm. could both be correct? explain

How many times larger is 6 × 10^12 than 2 × 10^7? a. 30,000 b. 3,000 c. 3,000,000 d. 300,000