Question 134325: fred buys a box of books at a car boot sale the box contains 7 hardback books and 8 soft back books and costs £8.37...diane buys a box containing 12 hardback books and 5 soft back books from the same stall at a cost of £10.95...given that all hardback books are sold for one price, x, and all soft back books for another, y, form simultaneous equations and solve them to find the cost of each type of book.
Answer by edjones(8007)   (Show Source):
You can put this solution on YOUR website! Let h=cost of a hardback book, s=cost of a soft back.
A) 7h+8s=8.37
B) 12h+5s=10.95
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B) 96h+40s=87.6 Multiply each side by 8
A) 35h+40s=41.85 Multiply each side by 5
-----------------subtract
===>61h=45.75
h=45.75/61=0.75
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7*.75 + 8s=8.37
5.25+8s=8.37
8s=8.37-5.25
8s=3.12
s=3.12/8=.39
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Check:
12*.75 + 5*.39 =10.95
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Ed
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