Answer:
a.4845ways.
b. 14535ways.
c. 3990ways
d. 1140ways
Step-by-step explanation:
Given data:
No of flavors available to customers = 20.
Solution:
This is permutation and combinations problem,
(a) how many ways can the customers choose 4 different ice creams if they are all of different flavors.
20C4
= n!/(n-k)!)k!
= 20!/(20-4)!)4!
= 20!/(16)!)4!
= 4845ways.
b) are not necessarily of different flavors
Let’s say any two same flavors can be chosen.
20C4 * 3!/2!
= 4845 * 3
= 14535ways.
c) contain only 2 or 3 flavors.
= 20C3 * 3!/2!
= 1140 * 3
= 3420
20C2 * 3
= 190 * 3
= 570.
No of 2 or 3 different flavors
= 3420 + 570
= 3990ways.
d) contain 3 different flavors.
20C3
= n!/(n-k)!)k!
= 20!/(20-3)!)3!
= 1140ways.
Answer:
1) 5
Step-by-step explanation:
(working on the others rq)
Answer:
45 girls
Step-by-step explanation:
- Remark
- There are only 2 choices for gender. So if the class is 60% girls, the there must be 100 - 60 = 40% for the boys.
- But we are told that the boys are 30 in number.
- Let x = the total number of students.
Solution
- 40/100 * x = 30 Change the % to a decimal
- 0.4 x = 30 Divide both sides by 0.4
- 0.4 x / 0.4 = 30 / 0.4 Do the division
- x = 30/0.4
- x = 75 students in total
Formula
Total of Boys and Girls = Number of boys + number of girls.
Givens
- Total = 75
- Number of boys = 30
Solution II
- 75 = x + 30 Subtract 30 from each side
- 75 - 30 = x +30 - 30
- 45 = x
- There are 45 girls in the class.
6,4 and or 8,7 should be the answer
BDs
CDs
Total
There is no change from $120 because she doesn't have enough money.
