Can someone tell me if I’m right?

The birth weights of newborn babies in the unites states follow in a normal distrubution with a mean of 3.4 kg and standard deviation of 0.6 kg. reaserches interested in studying how. children gain weights decide to take random samples of 100 newborn babies and calculate the sample mean birth weights for each sample

Graph the line with the given slope m and y-intercept b. m=-3,b=1

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?