There are 10 people in an office with 4 different phone lines. if all the lines begin to ring at once, how many groups of 4 people can answer these lines?

210

Step-by-step explanation:

We are given that

Total number of peoples=n=10

Number of different phone lines=r=4

We have to find the number of groups of 4 people can answer 4 lines when all lines begin to ring at once.

Using combination formula

Substitute the values in the given formula

Then , we get number of groups of 4 people can answer 4 lines=

Number o groups of 4 peoples=

Number o groups of 4 peoples=

Hence, 210 groups of 4 peoples can be made and answer these 4 lines.

question is incomplete.

the correct answers i think are b. and d.

give me brainliest if it is correct!