Math

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Cost of 4 books and 5 pens is 32 and cost of 5 books and 4 pens is 31 then find the cost of 1 book B=?

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4b + 5p = 32

5b + 4p = 31

Multiply first equation by 4 and second by 5.

16b + 20p = 128

25b + 20p = 155

Subtract first from second and solve for b.

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