1. Derek adds water to a pool at a rate of 12 gallons per minute and then reduces the

rate to 8 gallons per minute. Derek adds water to the pool for a total of 2 hours. Lett

be the time in hours that he adds water to the pool at the faster rate. Write algebraic

expressions to represent how many minutes he adds water to the pool at each rate.

answer: h

step-by-step explanation:

b. b < 1 might be the correct answer

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."