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Hoochie [10]
3 years ago
5

A small school bus contains eight first-graders and ten second-graders. if two children are ill, what is the probability that at

least one of them is a second-grader?
Mathematics
1 answer:
xenn [34]3 years ago
3 0
At least means :
1) one of them OR
2) two of them

\binom{10}{1} \times \binom{8}{1} \: \: here \: we \: say \:
we choose one of them from second graders and another one from first garders

that "or" which I mentioned means we have to use + (plus) to go to 2nd state that I've written

in 2nd we consider that
two of them are second graders in that case:
\binom{10}{2} \times \binom{8}{0} \:
so at last we've got this
\binom{10}{1} \times \binom{8}{1} + \binom{10}{2} \times \binom{8}{0} =

you have to know the formula that I'm using
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Step-by-step explanation:

456 devided by 4 equals 114

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A radio station advertises a contest with ten cash prizes totaling $5510. There is to be a $100 difference between each successi
My name is Ann [436]

Answer:

option C

c. least: $101

greatest: $1001

Step-by-step explanation:

A radio station advertises a contest with ten cash prizes totaling $5510. There is to be a $100 difference between each successive prize.

Sum of 10 prizes = 5510

100 is the difference. there is a common difference d=100

So its a arithmetic sequence

the sum formula for arithmetic sequence is

S_n = \frac{n}{2}(2a_1 +(n-1)d)

Sn = 5510, n=10 n d= 100 we need to find out first term a1

5510 = \frac{10}{2}(2a_1 +(10-1)100)

5510 = 5 (2a1 + 900)

5510 = 10a1 + 4500

Subtract 4500 on both sides

1010= 10a1

divide by 10 on both sides

a1 = 101

so first term that is least term is 101

To find out greatest term we use formula

a_n = a_1 + (n-1) d

a(10) = 101 + (10-1)100

= 101 + 900= 1001

greatest is 1001

4 0
3 years ago
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