Solve the system by graphing or using a table 2x+4y=12

Darcy deposited $390 into a savings account. as long as the account balance remains at or above $150, she does not have to pay a service fee for the account. for how many months can she withdraw $40 a month without having to pay service fees? a) 3 b) 5 c) 6 d) 9

The coverage of a base station of a telecommunication company forms a disk with a radius of (kilometers). let be the distance of a cellphone from a base station. assume that the location of cellphones in use are randomly uniformly distributed within the disk. calculate the mean and variance for the random variable.

Fracisco's game involves 3 green, 2 yellow, 4 red, and 3 black marbles. if he randomly draws three marbles from the bag, without replacement, what is the probability that he will draw yellow, and then red, and then black? a)1/192 b)1/72 c)3/220 d)1/55