Probability 2

Bag A contains 4 cards numbered 1, 4, 7, 11 and bag B contains 3 cards numbered 2, 6, 9.
Two cards were drawn at random, the first from Bag A and the second from Bag B. Calculate the probability, in simplest fractional form, that the two numbers have a sum of 10.

• 1/6
• 5/12
• 2/3
• 3/

In a group of fifteen students, three names begin with the letter B and four begin with a G. The remaining eight names begin with A, C, D, E, F, H, I and J respectively. The 15 names are placed in a box. The box is shaken and three names are drawn out. Find the probability that The first two names begin with G and the third name begin with B.

• 7/125
• 8/455
• 6/455
• 11/200

A bag contains 3 black balls and 5 white balls. Paul picks a ball at random from the bag, keeps it and then picks another ball. Calculate the probability that Paul picks two white balls.

• 11/28
• 5/14
• 13/28
• 9/14

A class contains 5 boys and n girls. The name of every student was written on a card and the cards were placed in a bag. Two cards were chosen successively without replacement from the bag. If the probability that both cards contain boys’ names is 1/12 , find the value of n.

• 8
• 9
• 10
• 11

Ali puts the seven counters in a bag. He takes, at random, a counter from the bag and does not replace the counter. He then takes, at random, a second counter from the bag. Calculate the probability that the number on the second counter is 2 more than the number on the first counter,

• 1/18
• 1/30
• 3/15
• 7/18

A bag contains 5 green balls and 3 yellow balls. Ronnie and Julie play a game in which they take turns to draw a ball from the bag at random without replacement. The winner of the game is the first person to draw a yellow ball. Julie draws the first ball. Find the probability that Ronnie wins the game.

• 15/56
• 1/8
• 9/56
• 3/14

• 11/9976
• 5/9976
• 85/13717
• 13/9976

• 7/41
• 8/47
• 5/39
• 6/41

• 4/15
• 7/8
• 1/5
• 2/5

Maria travels to school either by walking or by bicycle. The probability she cycles to school is 0.75.
If she walks, the probability that she is late for school is 0.1. If she cycles, the probability that she is late for school is 0.05. Draw a tree diagram and hence find  the probability that Maria is late for school.

• 0.0654
• 0.0564
• 0.0611
• 0.0625