The speedometer in kevin’s car reads in both miles/hour and kilometers/hour. what information is needed to convert between these two units?
the number of miles in 1 kilometer
the number of kilometers that are traveled in 1 hour
the number of miles that are traveled in 1 hour
the number of hours per 1 kilometer

In this problem, the speedometer reads two speed units: miles per hour and kilometers per hour. In this case, to convert one to the other, one has to convert miles to kilometers. Hence the information needed in this problem is A. the number of miles in 1 kilometer.

You need the number of miles per kilometer, or vice versa.

 The correct options are

Part A : option (a) the common difference is -10.

Part B : option (c) 3,  -2,  -7,  -12,  .   .   .

Step-by-step explanation:  We are given to solve the following two problems

PART A :  

We are given to select the statement that best describes the relationship between the successive terms in the following sequence :

9,   -1,   -11,    -21,   .   .   .

If a(n) denotes the n-th term of the given sequence, then we see that

Since the difference between any two consecutive term of the given sequence is -10, so

there is a common difference of -10.

Option (a) is CORRECT.

PART B :  

Given that a sequence is defined recursively using th efollowing formula :

We are to select the sequence that could be generated using formula (i).

Let f(n) = 1. Substituting n = 1, 2, 3, 4,  .  .  . in equation (i), we get

In this case, the sequence is 1, -4, -9, -14,  .  .  .

Let f(n) = 2. Substituting n = 1, 2, 3, 4,  .  .  . in equation (i), we get

In this case, the sequence is 2, -3, -8, -13,  .   .   .

Let f(n) = 3. Substituting n = 1, 2, 3, 4,  .  .  . in equation (i), we get

In this case, the sequence is 3, -2, -7, -12,  .   .   .

Let f(n) = 4. Substituting n = 1, 2, 3, 4,  .  .  . in equation (i), we get

In this case, the sequence is 4,-1, -6, -11,  .   .   .

Thus, the correct sequence that could be generated is 3, -2, -7, -12,  .  .  .

Option (c) is CORRECT.