Please helppp can someone please help me I am so confused on how to answer these

A; D; A; C; C

Step-by-step explanation:

1. S29 means the sum of the first 29 terms. Because it's an arithmetic sequence, the sum of the first x terms is (the first term + xth term)(x)/2

That means the answer to the first question is (7+70)(29)/2 = 1116.5 (A)

2. The sum of the first 18 terms is (56 + 5)(18)/2 = 549 (D)

3. The common difference is 3.5, making the 26th term 87.5. That makes the sum of the first 26 terms (7+94.5)(26)/2 = 1319.5 (A)

4. The question is asking for the sum of the first 28 terms. The first term is 50-4(1) = 46. The 28th term is 50-4(28) = -62. That makes the sum of the first 28 terms (46+(-62))(28)/2 = -224 (C)

5. The first x terms of a geometric sequence is the (first term - (x+1)th term)/(1-(ratio)).

That makes the sum ((1/3)-(729))/(1-3) = -(2186/3)/-2 = 1093/3 = 364 1/3 (C)

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."