A computer technician notes that 40% of computers fail because of the hard drive. If he repairs many computers a day, what is the probability that the first computer that has failed due to the hard drive is his 4th computer of the day? 0.0384
0.0864
0.1296
0.3456

The system of equations graphed below has how many solutions?

Kelly is a salesperson at a shoe store, where she must sell a pre-set number of pairs of shoes each month. at the end of each work day the number of pairs of shoes that she has left to sell that month is given by the equation s=300-15x , where s is the number of pair of shoes kelly still needs to sell and x is the number of days she has worked that month. what is the meaning of the number 300 in this equation

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?