[my experiment proved beyond a doubt that vitamin c can reduce the severity of colds, because i controlled the experiment carefully for every possible confounding variable. choose the correct answer below. a. the statement does not make sense because it is not always easy to discover confounding variables. b. the statement makes sense because every possible confounding variable can be eliminated through careful study. c. the statement makes sense because confounding variables are the only reason an experiment's results could be doubted. d. the statement does not make sense because confounding variables would not affect the reliability of the experiment.

How many triangles can be drawn with side lengths 4 centimeters, 4.5 centimeters, and 9 centimeters? explain

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?