You have 5 reindeer and you want to have 3 fly your sleigh. You always have your reindeer fly in a single-file line how many different ways can you arrange your reindeer

What is the value for this expression? 2e-5

Can anyone me with this question?

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?