A radar unit is used to measure speeds of cars on a motorway. the speeds are normally distributed with a mean of 90 km/hr. and a standard deviation of 10 km/hr. what is the probability that a car picked at random is travelling at more than 100 km/hr.

Trent wants to buy 2 packs of trading cards for 3 dollars each. the trading card packs that trent normally buys tend to come in packs of 6, 10, 12, or 15 cards. after selecting 2 packs, trent found that the first pack of cards cost 25 cents per card, and the second pack cost 30 cents per card. trent uses this information to write the equations below in order to compare c, the number of cards in each pack.