Mr. lester needs to store 23 science books for his class on a shelf @ the back of the classroom. each science book is 2.6 centimeters thick. if mr. lester stacks the science books on top of each other on the shelf, how tall does the shelf have to be?

Plz answer asap! i will reward brainliest and 12 points for these three questions!take notice: these three questions are completely different! 1) what is the percentage of sugar in the syrup made of 10 kg of water and 4 kg of suugar? 2) what was the original price if after 10% discount it became $450? 3) at first a price was decreased by 12%, then it was disounted again by an additional 5%. what is the percent of the total discount? , and remeber i will award brainliest and 12 points!