If a and b are two numbers such that (a + b) : (a - b) : ab = 14 : 4 : 45, then what is the value of (5a + 3b) : (6a - 4.8b)?

If all the girls in school B and school C participated in the function, find the ratio between the number of boys in school B and school C who participated in the function.

Which of the following examples represents an inverse proportional relationship (reverse movement)?