Peter paid $79.80 for renting a tricycle for 6 hours. What was the rate per hour for renting the tricycle? (Input only numeric values and decimal point, and report prices to two decimal places, such as 12.30.)

the answer is 31.27mph

i agree because i see the other persons thinking is clear

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."