A school social group has 30 seniors, 38 juniors, 24 sophomores, and 18 freshmen. They need to choose a president, an assistant, and an accountant. The president must be a senior and the assistant must not be a freshman. How many different ways can they pick the officers?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ab=4 and bc=3, find ah, ch and bh.

Asmall business produces and sells balls. the fixed costs are $20 and each ball costs $4.32 to produce. each ball sells for $8.32. write the equations for the total cost, c, and the revenue, r, then use the graphing method to determine how many balls must be sold to break even.

The sum of the squares of two numbers is 8 . the product of the two numbers is 4. find the numbers.