Describe how to round 678 to the nearest hundredth

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)

Ana earns 2.5% simple interest on $2,000 in her savings account. she does not make any deposits or withdrawals. after 3 years, how much interest will ana have earned on her savings account?

Compute the standard deviation of the following set of data to the nearest whole number. 10, 10, 15, 20, 25