In one minute, evan can do nine less than four times the number of push-ups that lucy can do. if they did 61 push-ups in all, how many more push ups did evan do than lucy

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?

Since we have computer algebra systems that can solve polynomial division problems for us, why is it necessary to learn how to do these things by hand?

35 is what percent of 700? show your work