Answer:
Joseph's bill was $9.6.
Step-by-step explanation:
Given:
Number of cold drinks = 4
Number of subway sandwiches = 7
Total cost of cold drinks and sandwiches = $21.60
The sandwiches cost twice as much as the cold drinks
To Find:
How much was Joseph's bill = ?
Solution:
Let the cost of one cold drink be x
The cost of sandwich be y
The sandwiches cost twice as much as the cold drinks
then
y = 2x--------------------------------------(1)
Now the total amount can be represented as
4x+7y =21.60-----------------------------(2)
Substituting (1) in (2)
4x+7(2x) =21.60
4x+14x =21.60
18x =21.60
[tex]x = \frac{21.60}{18}[/tex]
x = 1.2--------------------------------------(3)
The cost of one cold drink is $1.2
On substituting (3) in(1)
y = 2(1.2)
y = 2.4
The cost of one sandwich is $2.4
Now ,Joseph and his date had two cold drinks and three Subway sandwiches. So Joseph bill will be
=>[tex]( 2 \times \text{ cost of one cold drink} )+ (3 \times \text{ cost of one subway sandwich})[/tex]
=>[tex](2 \times 1.2) + (3 \times 2.4)[/tex]
=>(2.4) + (7.2)
= 9.6
