If y varies directly as x and y=8 when x=3 what is the value of y when x=9?
A 8/3
B 27/8
C 14
D 24

What number should be added to both sides of the equation to complete this square? x^2-10x=7

You were told that the amount of time lapsed between consecutive trades on the new york stock exchange followed a normal distribution with a mean of 15 seconds. you were also told that the probability that the time lapsed between two consecutive trades to fall between 16 to 17 seconds was 13%. the probability that the time lapsed between two consecutive trades would fall below 13 seconds was 7%. what is the probability that the time lapsed between two consecutive trades will be between 14 and 15 seconds?

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class