How many solutions does the system of equations have? x - 3y = 15 and 3x - 9y=45

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )

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.

Imade a beaded necklace that was 2/6 blue, 3/5 green and the rest were white. did the necklace have more blue or green how many white beads did it have.