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Each of the integers 1-25 is written on an individual card and placed in a hat. You

randomly draw a card. How many favorable outcomes are there for choosing a card
with an odd number?
Ο Α. 2
OB. 11
O C. 13
OD. 25

User Srgsanky
by
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1 Answer

9 votes

Answer:

Explanation:

Comment

If you know this formula

tn = t1 + (n - 1)*d then you don't even have to count how many odd numbers there are. If you don't know the formula, then you have to count how many odds there are between 1 and 25 inclusive. Just to save you the trouble, there are 13.

Givens

1 = t1

25 = tn

d = 2

Solution

25 = 1 + (n - 1)*2 Subtract 1 from both sides?

25-1 = 1-1 + (n - 1)*2 Combine

24 = (n - 1) * 2 Divide by 2

24/2 = (n - 1)*2/2

12 = n - 1 Add 1 to both sides

12 + 1 = n - 1 + 1 Combine

13 = n

Answer

So you have 13 cards that will bring success.

User SteveS
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