Math Games

Archive for June, 2006

Below are some multiplication free Math Games. 

Multiplication free math game 1

Ray has four married brothers, three married sisters, and six unmarried cousins. His parents invite them all for Christmas and give their children and spouses gifts costing $20 each, and their nephews and nieces gifts costing $15 each. 

How much do Ray's parents spend on Christmas gifts? (Assuming Ray is married) 

Multiplication free math game 2

A river flows at a speed of 3 miles per hour over its first 30 miles, twice as fast over its second 20 miles, and three times as fast during the last 10 miles. 

At what speed does the river flow in the last 10 miles? 

Multiplication free math game 3

A soccer player receives the ball at a speed of 25 miles per hour (mph) and passes it twice as fast to a player who kicks it into the goal one and one half times faster than that, scoring a goal. 

At what speed is the ball kicked into the goal? 

For the answers to these multiplication free Math Games, click here.

Question: math help urgent!!!!!?

If a patient is allergic to penicillin, the probability of a reaction to a new drug X is 0.5. If the patient is not allergic to penicillin, the probability of a reaction to drug X is 0.1. Eight percent of the population is allergic to penicillin. A patient is given drug X and has a reaction. Find the probability that the patient is allergic to penicillin. Round your answer to the nearest thousandth.

A football team plays 80% of its games at home and 20% away. It typically wins 80% of its home games and 55% of its away games. If the team wins on a certain Saturday, what is the probability that it played at home? Round your answer to the nearest thousandth.

Answer: Penicillin: .92 (not allergic) * .1 = .092. .08 (allergic) * .5 = .04. So, if you gave 1000 people the shot, 920 would not be allergic and 92 of them would have a reaction. 80 people would be allergic, and 40 of them would have a reaction. So, you'd have 132 people with a reaction, 40 of whom would be allergic to the stuff. 40/132 = .303. So, the odds would be 30.3% that anyone who had a reaction was allergic.

Football: .8 (home) *.8 = .64. .2 (away) * .55 = .11. So, if it played 100 games, 80 at home and 20 away, it would win 64 home games and 11 away games. Of the 75 total wins, 64 would be home wins. So, for any win, the odds would be 64/75 = 85.3% that it was at a home game.

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