9. The probability that a two digit number selected at random will be a multiple of 3 and not a multiple of 5 is
Answers
Answered by
14
Step-by-step explanation:
There are 90 two digit numbers(99–9). Out of this there are 6 numbers divisible by 15(15, 30, 45, 60, 75, 90), which are also divisible by 5. Therefore, the favorable cases are 30–6=24. Hence, the required probability is 24/90 = 4/15
Answered by
3
Answer:
24/90 = 4/15 is the answer
Step-by-step explanation:
All two digit numbers are:
{10,11, 12, 13, 14, 15, .... 99}
= (99-10) + 1 = 90
Digits divisible by 3 are: {12, 15, 18, ... 99}
As they form an AP,
12 + (n-1)×3 = 99
=> 3(n - 1) = 87
=> n - 1 = 29
=> n = 30
Digits divisible by both 3 and 5(i.e. divisible by 15) {15, 30, 45, 60, 75, 90} = 6
Therefore, Numbers divisible by 3 but not 5 = 30 - 6
= 24
Probability = 24/90
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