Kaya rented a limousine. There was a one-time charge of $100 dollars, plus an hourly rate of $45. Her total cost for the night was $347.50. How many hours did Kaya rent the limo for?

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of