Problema Solution

Ruth can buy 5 bottles of water and 2 cans of soda for $5.90. She can buy 3 bottles of water and 7 cans of soda for $10.21. Find the cost of 1 bottle of water and 1 can of soda.

Answer provided by our tutors

let the price of

bottle of water : w

can of soda : c

now,

5 bottles and 2 cans cost $5.90 .

=> 5w + 2c = 5.90(1)

3 bottles and 7 cans cost $10.21

=> 3w + 7c = 10.21(2)

Now, multiplying (i) with 7, and (ii) with 2,

35w + 14c = 41.30(3)

6w + 14c = 20.42(4)

subtracting 4 from 3,

29w = 20.88

=> w = $0.72,

and, 

5w + 2 c = 5.90

=> 2c = 5.90 - 5w = 5.90 -5*0.72 = 5.90-3.60 = 2.30

=> 2c = 1.15

so, total price of a can and a bottle will be,

$1.15 + $0.72 = $1.87