Express the series using sigma notation 5 - 10 + 20 - 40 + 80 - ...

∑

i=1

(

−

1

)

i

+

1

⋅

5

⋅

2

i

−

1

Explanation:

∑

=

5

−

10

+

20

−

40

+

80

−

...

.

.

Here we have a sequence of terms with alternating sign beginning positive.

To achieve this we need a term

(

−

1

)

1

+

1

for

i

from

1

→

n

Only considering the absolute values of the terms, we have sequence where

a

n

=

2

⋅

a

n-1

and

a

1

=

5

To achieve this we need a term

5

⋅

2

i

−

1

for

i

from

1

→

n

Combining these results we have our sum in sigma notation:

n

∑

i=1

(

−

1

)

i

+

1

⋅

5

⋅

2

i

−

1

answer:

step-by-step explanation:

here, the total dishes = 10

dishes having meat = 3 ( chicken, meatloaf and hamburger )

thus, the probability of having meat on the chosen dishes = number of dishes having meat / total dishes

=

therefore, the probability of not having meat = 1- the probability of having meat on the chosen dishes

=

=

=

⇒ option b is correct.