What is the theoretical probability of selecting a heart or a spade from a standard deck of cards

Ascientist places 24 cells in a petri dish. she knows the cells grow at an exponential rate, doubling in number every hour. how long will it take (in hours) for there to be 1100 cells in the dish? time to 1100 cells: 5.51832530 hours how long will it take to reach 110 cells? time to 110 cells : 2.1963972 hours what is the average rate of change in the number of cells between 9 hours and 11 hours? average rate of change: cells per hour what is the instantaneous rate of change after 7 hours? instantaneous rate of change: cells per hour note: you can earn partial credit on this problem.

If the diagram polygon abcd is a reflection across ef to make polygon a'b'c'd'.

The box plots show the distributions of the numbers of words per line in an essay printed in two different fonts.which measure of center would be best to compare the data sets? the median is the best measure because both distributions are left-skewed.the mean is the best measure because both distributions are left-skewed.the median is the best measure because both distributions are symmetric.the mean is the best measure because both distributions are symmetric