Mathematics

# Vicki puts 10 books on a shelf. The 10 books take up 28 centimeters. What is the mean (average) thickness of her books? = 2.8 cm The shelf is 120 centimeters long. Vicki fills the shelf with a mixture of books like the first ten books. Estimate how many books she can get on the 120 cm shelf. Please show your working out. Thanx

$the\ mean\ hickness\ of\ Vicki's\ books= \frac{28\ cm}{10} =2.8\ cm\\\\28\ cm\ \rightarrow\ 10\ boocks\\120\ cm\ \rightarrow\ x\\\\x= \frac{120\cdot 10}{28} \approx42.9\\\\Ans.\ Vicki\ can\ put\ 42\ books.$