if they bought a total of 20 bottles that cost $9.65 how many bottles of orange juice did they buy

Question

For one game they bought Apple juice that costs $0.45 a bottle and orange juice that cost $0.50 a bottle 

Answer 1

Let A = # bottles of apple juice

Let J = # bottles of orange juics

           [o looks too much like a zero]

 

A + J = 20      since they bought 20 bottles total

 

Total money spent is .45(# bottles Apple juice) plus

.5(# bottles of Orange juice) so the equation is:

 

.45A + .5J = 9.65

 

We have 2 equations with two unknowns:

 

equation 1)   A + J = 20

equation 2)  .45A + .5J = 9.65

 

From equation one solve for A in terms of J

A = 20 - J

Replace A with 20-J in equation 2 and solve for J

 

.45(20-J) + .5J = 9.65

9 - .45J + .5J = 9.65

.05J = .65

J = 13

 

They bought 13 bottles of orange juice

[and 7 bottles of apple juice]

 

 

Hope this helps.  Let me know if you have questions.