Answer:
(a) 120 choices
(b) 110 choices
Step-by-step explanation:
The number of ways in which we can select k element from a group n elements is given by:
So, the number of ways in which a student can select the 7 questions from the 10 questions is calculated as:
Then each student have 120 possible choices.
On the other hand, if a student must answer at least 3 of the first 5 questions, we have the following cases:
1. A student select 3 questions from the first 5 questions and 4 questions from the last 5 questions. It means that the number of choices is given by:
2. A student select 4 questions from the first 5 questions and 3 questions from the last 5 questions. It means that the number of choices is given by:
3. A student select 5 questions from the first 5 questions and 2 questions from the last 5 questions. It means that the number of choices is given by:
So, if a student must answer at least 3 of the first 5 questions, he/she have 110 choices. It is calculated as:
50 + 50 + 10 = 110
Write a recursive and explicit formula for each option.
Save a nickel on the first day of the month and then double the amount each day for a month
=> a1 =0.05
=> a2 = a1* 2 = 0.05*2
=> a3 = a2*2 = a1* 2*2
..............................................
=>recursive an =
=> explicit an = 0.05*
Start their savings by saving $10 on the first day and then $10 each day of the month
=> a1 = 10
=> a2 = a1 + 10 = 20
=> a3 = a2 +10 = 20 +10 =30
........................................................
=> recursive an =
=> explicit an = 10 + 10( n-1)
Hope it will find you well.