Sam opened a money-market account that pays 4% simple interest. he started the account with $7,000 and made no further deposits. when he closed the account, he had earned $560 in interest. how long did he keep his account open?

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

One number is 4 less than 3 times a second number. if 3 more than two times the first number is decreased by 2 times the second number, the result is 11. use the substitution method. what is the first number?