20. The diagram below shows a closed system of two tanks that each contain water. 140 mL of water
140 mL of water
at 20°C
at 72°C
When the valve between the two tanks of water is opened, the temperature of the water in each tank
changes. What is the equilibrium temperature to the nearest whole degree Celsius?
Record your answer on the answer document.

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Which is not true about oxygen-17 and oxygen-18?

Which of the following are not typically included in the periodic table? a. atomic mass b. element symbol c. isotopes d. number of electrons