Arif and keisha go to a restaurant for dinner. their meals total $13.75.the tax is 5%
how much tax is added to their bill ?
arif and keisha want to leave a 15% tip based on the bill and the tax combined. how much should they leave ? explain you

The total cost of the dinner meals taken by Arif and Keisha = $13.75
Percentage of tax that need to be given = 5%
Then
Amount of tax that needs to be given = (5/100) * 13.75 dollars
                                                           = 13.75/20 dollars
                                                           = 0.687 dollars
                                                           = 0.69 dollars
So
The total amount that needs to be 
paid for dinner including tax = (13.75 + 0.69) dollars
                                             = 14.44 dollars
Percentage of tips that they both want to leave = 15%
Then
Amount of tips that need to be given = (15/100) * 14.44
                                                           = 216.6/100 dollars
                                                           = 2.17 dollars
So
The total amount that they should leave = (14.44 + 2.17) dollars
                                                                 = 16.61 dollars
So they should leave a total of $16.61 in the restaurant.

, and

for

step-by-step explanation:

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

1 the 1st term, 3 the 2nd term, 6 the 3rd term,etc.

note the following:

from the 1st term (1) to the 2nd term (3), we go up by 2,from the 2nd term (3) to the 3rd term (6), we go up by 3from the 3rd term (6) to the 4th term (10), we go up by 4, andfrom the 4th term (10) to the 5th term (15), we go up by 5.

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