Using the combination formula, it is found that:
1. A. 7 combinations are possible.
B. 21 combinations are possible.
C. 1 combination is possible.
2. There are 245 ways to group them.
<h3>What is the combination formula?</h3>
is the number of different combinations of x objects from a set of n elements, given by:

Exercise 1, item a:
One letter from a set of 7, hence:

7 combinations are possible.
Item b:
Two letters from a set of 7, hence:

21 combinations are possible.
Item c:
7 letters from a set of 7, hence:

1 combination is possible.
Question 2:
Three singers are taken from a set of 7, and four dances from a set of 10, hence:

There are 245 ways to group them.
More can be learned about the combination formula at brainly.com/question/25821700
Well if you have 60 and she has 120 i will set it out as a sequence week by week
60,67,74,81,88,95,102,109,116,123,130,137,144,151,158,165,172,179,186,193,200,207,214,221,228,235,242,249,256,263,270
120,125,130,135,140,145,150,155,160,165,170,175,180,185,190,195,200,205,210,215,220,225,230,235,240, 245,250,255,260,265,270
it would take 31 weeks and the total is 270
Answer:42
Step-by-step explanation: