(geometric proofs)
Given: 2c=d-4a;c=2a-3b;d=a+2b
Prove: b=7/5 a

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made

Ann and betty together have $60 ann has $9 more than twice betty’s amount how much money dose each have