If there are 31,556,952 seconds in one year, which of the following is the best estimate for the number seconds there are in eight years?

approximately 2,400,000 seconds
approximately 24,000,000 seconds
approximately 240,000,000 seconds
approximately 2,400,000,000 seconds

The students at jefferson middle school are raising money for a charity by selling t-shirts and hats. the number of t-shirts sold was 3 times the number of hats. the profit was $5 for each t-shirt sold and $2.50 for each hat sold. the students raised $840 for the charity. they used the system below to analyze their success and found the solution to be (144, 48). 5x+2.50y=840 x=3y how much did they earn from t-shirt sales?