the age of two girls are in the ratio 5 ratio 7 8 year ago their ages were in the ratio 7 ratio 13 find their present ages​

What is the value of y? round to the nearest tenth

Brainlest answer can you find the area and circumference of a circle given the radius or diameter? if its yes or no explain why

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.