Ed is doing a survey of popular colors for cars for a school report. He decides to take a sample by sitting near a busy intersection and noting the colors of the cars as they go by him. Ed counts 23 black cars, 9 red cars, 17 blue cars, 25 white cars and 21 silver cars during 20 minutes of watching. How many more white and blue cars are there than silver and red cars?

There are 12 more of white and blue cars than silver and red cars

Step-by-step explanation:

Step 1 :

Number of black cars counted by Ed = 23

Number of red cars counted by Ed = 9

Number of blue cars counted by Ed = 17

Number of white cars counted by Ed = 25

Number of silver cars counted by Ed = 21

We need to determine how many more white and blue cars are there than silver and red cars

Step 2  :

Total of white and blue cars = 25 + 17 = 42 cars

Total of sliver and red cars = 21 + 9 = 30 cars

Difference  = 42 - 30 = 12 cars

Hence there are 12 more of white and blue cars than silver and red cars

Step 3 :

Answer :

There are 12 more of blue and white cars than red and silver cars

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for