CLASS 8 SPOT TEST
1. WHAT IS THE PROBABILITY THAT AN INTEGER CHOSEN AT RANDOM BETWEEN 1 TO 10 INCLUSIVE IS EVEN?
2. A BAG CONTAINS 5 WHITE, 4 BLACK AND 1 BLUE BALLS. ONE BALL IS CHOSEN AT RANDOM. WHAT IS THE PROBABILITY THAT IT IS BLACK?
3. FIND THE PROBABILITY OF GETTING AN ODD NUMBER IN A SINGLE TOSS OF A FAIR DIE?
4. A FAIR DIE IS THROWN 900 TIMES. FIND THE NUMBER OF TIMES YOU WOULD EXPECT TO GET A 6.
5. THE PROBABILITY THAT IT WILL BE CLOUDY TOMORROW IS 0.45. WHAT IS THE PROBABILITY THAT IT WILL NOT BE CLOUDY TOMORROW?
Step-by-step explanation:
1. Of the following 10 numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
Only these 5 are even: 2, 4, 6, 8, 10.
The probability on an even number is 5 / 10 = 0.5 = 50%
2. The total number of balls is 10.
5 WHITE, 4 BLACK AND 1 BLUE
The probability on a black ball is 4 / 10 = 0.4 = 40%
3. A fair die can show the following 6 numbers 1, 2, 3, 4, 5, 6.
Only these 3 are odd: 1, 3, 5.
The probability on an odd number is 3 / 6 = 0.5 = 50%
4. The probability of a six is 1 / 6. If the die is cast for 900 times you can expect it to be 900 * 1 / 6= 900/6 = 150. The number of times you would expect a 6 would be 150.
5. If the probability on a cloudy tomorrow is 0.45, then in mathematics, that defines the propability for an non cloudy tomorrow as 1 - 0.45 = 0.55, which is 55%.
(The total should always add up to 100%).
