Class 9 Coins and Dice — practice questions with answers
Statistics · 5 sample questions from the school syllabus. Try each one, then open the answer and the worked solution.
1. A coin is tossed 100 times and a head appears 56 times. What is the empirical probability of getting a head?
A0.56
B0.44
C0.50
D5.6
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Answer: A) 0.56
Empirical probability = number of heads / total tosses = 10056 = 0.56.
2. A die is rolled 250 times. The empirical probability of getting a 3 is 0.16. How many times did 3 appear?
A40
B80
C44
D36
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Answer: A) 40
Frequency = 0.16 x 250 = 40.
3. A die is rolled some number of times. The number 2 appeared 45 times with empirical probability 0.18. How many times was the die rolled?
A275
B250
C225
D500
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Answer: B) 250
0.18 = total45, so total = 0.1845 = 250.
4. A die is rolled and the number is noted. In 600 trials, the empirical probability of getting a number that is a perfect square (1 or 4) was found to be 0.35. Face 1 occurred 96 times. How many times did face 4 occur?
A124
B228
C114
D104
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Answer: C) 114
Perfect squares (1 or 4) total = 0.35 x 600 = 210. Face 4 = 210 - 96 = 114.
5. Two students record the same coin-and-die game (one coin + one die together). Out of 800 plays: 'tail with a 6' occurred 64 times and 'head with a 6' occurred 70 times. What is the empirical probability of getting a 6 on the die (with either coin face)?
A0.1675
B0.08
C0.0875
D0.335
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Answer: A) 0.1675
A 6 on the die = (tail,6) or (head,6) = 64 + 70 = 134 plays. P = 800134 = 0.1675.