Mark bought 20 toy cars for $15. Tina bought 12 toy cars for $8. Use cross
products to determine if the given rates
are proportional.
A) Yes, the two rates are proportional.
B) No, the two rates are not proportional.

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?

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.

The multiplicative property of equality states that for real numbers a, b, c, and d, if a = b and c = d, then ac = bd. true false