find the probability of making a five digit number form 2,3,4,7,8 in such a way that 7 is the first number and 8 is the last number

Translate the word phrase into a math expression. 15 fewer than the product of 4 and a number. (pls immediately)

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days

A6 ounce bottle of dressing costs $1.56 a 14 ounce bottle costs $3.36 a 20 ounce bottle costs $5.60 which has the lowest cost per ounce