An elevator descends into a mine shaft at the rate of 5 m/min. If the descend starts from 15m above the ground, by how long will
2 answers:
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Answer:
In 68229 ways can the quiz be selected such that there is atleast three multiple choice questions
Step-by-step explanation:
Given:
Number of True or false questions= 10
Number of multiple choice questions= 20
To Find:
How many ways can 5 questions can be selected if there must be at least three multiple choice questions =?
Solution:
Combination
A combination is a mathematical technique that determines the number of possible arrangements in a collection of items where the order of the selection does not matter. In combinations, you can select the items in any order.
The question States there sholud be ATLEAST 3 multiple choice question,
So, we may have
(3 Multiple choice question and 2 true or false question) or
(4 Multiple choice question and 1 true or false question) or
(5 Multiple choice question and 0 true or false question)
Required Number of ways = (20C3 X10C2) +(20C4 X10C1) + (20C5 X10C0)
Required Number of ways
Required Number of ways = ( 1140 x 42) + (4845 x 10) +(15504 x 1)
Required Number of ways = 47880+48450+15504
Required Number of ways = 68229