Tony purchases 20 black pens along with some blue pens. He spends $155 in total. The black pens cost $6 each and the black pens cost $5 each. If b
represents the number of blue pens, which of the following equations can be
used to determine how many blue pens Tony purchased?

How many different three-digit numbers can be formed using the digits 1 comma 2 comma 9 comma 6 comma 4 comma 3 comma and 8 without repetition? for example, 664 is not allowed.

Find the solution(s) to x^2-14+49=0

Idon't want to fail summer school.the probabilities of contamination in medicine capsules due to the presence of heavy metals and different types of microbes are given in the table.the probability of capsule b having microbial contamination is (the same as, greater than, less than) the probability of capsule d having it.