Math

posted by .

Frank has a 65% chance of receiving an A grade in geology, a 60% chance of receiving an A grade in mathematics, and a 77% chance of receiving an A grade in geology or mathematics (or both). Find the probability that he receives A grades in both geology and mathematics.

I get: P(geo and math) = P(geo) + P(math) - P(geo or math)
= 0.65 + 0.60 - 0.77
= 1.25 - 0.77
= 0.48

• Math -

You need to make up your mind. Is the .77 for both or either-or?

I would assume that the above data (.77) is not needed.

To find the probability of both/all events occurring you need to multiply the probability of the individual events.

.65 * .60 = .39

Similar Questions

1. english

34. The Chinese love .… strangers. (A) of receiving (B) to receiving (C) receiving (D) receive i don't know
2. Math

The game of dots is played by rolling a fair die and receiving \$1 for each dot showing on the top face of the die. What cost should be set for each roll if the game is to be considered a fair game?
3. Research & Evaluation I

I have an airplane that has an ignition system that works like this. There are 2 energy producing devices, called magnetos that "fire" the spark plugs, 2 per cylinder. There is a 1 in a 1000 chance that one will fail. What is the chance …
4. Statistics - can someone check me

Frank has a 65% chance of receiving an A grade in geology, a 60% chance of receiving an A grade in mathematics, and a 77% chance of receiving an A grade in geology or mathematics (or both). Find the probability that he receives A grades …
5. Math

You estimate there is an 80% chance you will get an A on your math final, and a 75% chance you will get an A for your semester grade. What is the probability that both will happen?
6. waist water treatment

1/Why do the following components need to be removed from sewage under current law before it can be discharged on the surface water?