SOLUTION: the total cost of 2 books and 7 pens is 79 rs and the total cost of 7 books and 5 pens is 77 rs. find the cost of1 book and 2 pens...

Algebra ->  Equations -> SOLUTION: the total cost of 2 books and 7 pens is 79 rs and the total cost of 7 books and 5 pens is 77 rs. find the cost of1 book and 2 pens...       Log On


   

Question 1095931: the total cost of 2 books and 7 pens is 79 rs and the total cost of 7 books and 5 pens is 77 rs. find the cost of1 book and 2 pens...
Found 4 solutions by josgarithmetic, Naveedshahzad062@gmail.com , MathTherapy, ikleyn:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
b, book price
p, pen price
system%282b%2B7p=79%2C7b%2B5p=77%29
Multiply first equation by 7;
Multiply second equation by 2:

system%2814b%2B49p=553%2C14b%2B10p=154%29
Subtract this second of these from the first of these.

39p=399

p=10.23

From 2b%2B7p=79,
solving for b gives b=%2879-7%2Ap%29%2F2
b=%2879-7%2A10.23%29%2F2
b=3.69

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One book, highlight%28b=3.69%29
One pen, highlight%28p=10.23%29
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Sum for 1 book and 2 pens:
3.69%2B2%2A%2810.23%29
highlight%28highlight%2824.15%29%29,rs

Answer by Naveedshahzad062@gmail.com (1) About Me  (Show Source):
You can put this solution on YOUR website!
b = Rs 35.81 Approximately and p = Rs 20.46 Approximately

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

the total cost of 2 books and 7 pens is 79 rs and the total cost of 7 books and 5 pens is 77 rs. find the cost of1 book and 2 pens...

Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.
Either the condition contains an error (= is wrong), or the problem makes no sense.


Such problems EITHER have an EXACT solution, OR have no solutions at all.


The term and the conception "approximate solution" is NOT APPLICABLE for this problem.