Answer:
i dont know mabey some one else knows
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
Answer:
Step-by-step explanation:
The diameter of each curved path is 200 feet. Since the two curved semi circular paths are equal, they would form a circle. It means that the distance around the two semi circular paths would be the circumference of the circle. Formula for determining the circumference of the circle is π × diameter. It becomes
200 × 3.14 = 628 feet
Total distance around the track would be
300 + 300 + 628 = 1228 feet
5280 feet = 1 mile
1228 feet = 1228/5280 = 0.23 mile
If he runs around the track exactly 15 times, it means that the number of miles covered is
0.23 × 15 = 3.45 miles
Since he will collect $4.50 for every mile he runs, the amount of money that he collected is
4.5 × 3.45 = $15.5
Answer:
Step-by-step explanation:
we have
----> equation A
----> equation B
Solve the system by substitution
step 1
isolate the variable x in the equation A
----> equation A1
step 2
Substitute the equation A1 in the equation B
Solve for y