Basic Probability (CIE IGCSE Maths: Extended)

Tanya plants some seeds.
When a seed produces flowers, the probability that the flowers are red is 0.6 and the probability that the flowers are yellow is 0.3.

Tanya has a seed that produces flowers.
 
Find the probability that the flowers are not red and not yellow.

Suleika has six cards numbered 1 to 6.

She takes one card at random, records the number and replaces the card.

[1]

[1]

The diagram shows 5 cards.

Donald chooses a card at random.

[1]

[1]

Here is a four sided spinner.
The spinner is biased.

The table shows the probabilities that the spinner will land on 1 or on 3

The probability that the spinner will land on 2 is the same as the probability that the spinner will land on 4

Work out the probability that the spinner will land on 4.

Shunya is going to spin the spinner 200 times.

Work out an estimate for the number of times the spinner will land on 3.

Carol spins a spinner 80 times.

The table shows information about her results.

Dan spins this spinner 300 times.

Work out an estimate for the number of times that Dan will get an L.

The table shows the probabilities that a biased dice will land on 2, on 3, on 4, on 5 and on 6

Neymar rolls the biased dice 200 times.

Work out an estimate for the total number of times the dice will land on 1 or on 3.

There are girls, boys and some adults in a room.
Jenny selects at random one of these people.

The probability that Jenny selects a girl is 

Work out the probability that Jenny selects an adult.

There are only red counters, blue counters and purple counters in a bag.
The ratio of the number of red counters to the number of blue counters is 3 : 17

Sam takes at random a counter from the bag.
The probability that the counter is purple is 0.2

Work out the probability that Sam takes a red counter.

Four friends each throw a biased coin a number of times.
The table shows the number of heads and the number of tails each friend got.

The coin is to be thrown one more time.

Which of the four friends' results will give the best estimate for the probability that the coin will land heads?
Justify your answer.

Paul says,

"With this coin you are twice as likely to get heads as to get tails."

Is Paul correct?
Justify your answer.

The coin is to be thrown twice.

Use all the results in the table to work out an estimate for the probability that the coin will land heads both times.

There are 54 fish in a tank.
Some of the fish are white and the rest of the fish are red.

Jeevan takes at random a fish from the tank.
The probability that he takes a white fish is

Work out the number of white fish originally in the tank.

There are  counters in a bag.
Each counter in the bag is either red or blue so that

the number of red counters : the number of blue counters = 

 is going to put some more red counters in the bag so that

the probability of taking at random a red counter from the bag is 

Work out the number of red counters that is going to put in the bag.

Becky has a biased 6-sided dice.

The table gives information about the probability that, when the dice is thrown, it will land on each number.

Number	1	2	3	4	5	6
Probability		0.18			0.26

Becky is going to throw the dice 200 times.

Work out an estimate for the number of times that the dice will land on an even number.