Question

Your family goes to a restaurant for dinner. There are 7 people in your family. Some order the chiken dinner for $ 12 dollars and some order the steak dinner for $ 17 dollars. If the bill was $ 109 dollars, how many people ordered each dinner?​

Answer 1

The number of people who ordered steak dinner is 5

The number of people who ordered chicken dinner is 2

Explanation:

Given as :

The total number of people went for the dinner = 7

The total bill price for the dinner = $ 109

The price for the chicken dinner = $ 12

The price for the steak dinner = $ 17

Let The number of people who ordered chicken dinner = c

And The number of people who ordered steak dinner = s

Now, According to question

The total number of people went for the dinner = The number of people who ordered chicken dinner + The number of people who ordered steak dinner

Or, c + s = 7

And The total bill price for the dinner = The price for the chicken dinner × The number of people who ordered chicken dinner + The price for the steak dinner × The number of people who ordered steak dinner

Or, $ 12 × c + $ 17 × s = $ 109

Now, solving the equations

$ 12 × ( c + s ) = $ 12 × 7

Or, $ 12 × c + $ 12 × s = $ 84

Or, ( $ 12 × c + $ 17 × s ) - ( $ 12 × c + $ 12 × s ) = $ 109 - $ 84

Or , ( $ 12 × c - $ 12 × c ) + ( $ 17 × s - $ 12 × s ) = $ 25

Or, ( 0 ) + ( $ 5 s ) = $ 25

∴ s =
`(25)/(5)`

I.e s = 5

So, The number of people who ordered steak dinner = s = 5

Put the value og s in Eq A

∵, c + s = 7

or, c = 7 - s

Or, c = 7 - 5

I.e c = 2

So , The number of people who ordered chicken dinner = c = 2

Hence The number of people who ordered steak dinner is 5

And The number of people who ordered chicken dinner is 2 Answer