Which answer represents the series in sigma notation?

1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64

7

a. ∑ 2^j-1

j=1

7

b. ∑ 1/2(j+1)

j=1

7

c. ∑ 1/2 ^j-1

j=1

7

d. ∑ 1/2j+1

j=1

What is the upper quartile in the box plot?

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

The marked price of an article is 25% above its selling price and the cost price is 30% less than its marked price . find the discount percent and gain percent. only a brainlest can solve it i will mark you brainlest