A father who is 42 years old has a son and a daughter. The daughter is three times as old as the son. In 10 years, the sum of all their ages will be 100 years. How old are the two siblings at present?

Asmall (but heavy) particle placed in a glass of water will follow a zigzag motion because the particle will bounce off of the water molecules it meets. this is called brownian motion. a physicist simulates this on a computer, by varying the distance a particle can travel (called the mean free length), on average, before it collides with a water molecule and assigning the change in motion to be one of 8 directions, each with a similar probability. by running the simulated particle (with the same mean free length) many times she determines that it should take 15 seconds, on average, for the particle to fall to the bottom, with a standard deviation of 1.5 seconds. next she lets a real particle fall through a glass of water and finds that it took 18 seconds. what does she conclude, and why?

What is the number 321,000,000 in scientific notation? also what is the number? ?

Powerful women's group has claimed that men and women differ in attitudes about sexual discrimination. a group of 50 men (group 1) and 40 women (group 2) were asked if they thought sexual discrimination is a problem in the united states. of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem. if the p-value turns out to be 0.035 (which is not the real value in this data set), then at = 0.05, you should fail to reject h0. at = 0.04, you should reject h0. at = 0.03, you should reject h0. none of these would be a correct statement.