For the method of false position to work reliably, the algebraic formulation of the problem must involve a linear function of the unknown variable. Here's a problem that works:
A man lent his friend some money. A year later, the friend gave the money back, along with 20% interest, and the total money he gave back was $96. How much money was originally lent?
Solution: Try $10. 20% interest on $10 is $2, so he would get back $12, which is 1/8 the amount that we want. Therefore, 8*10 should work as a solution, and indeed it does: 20% interest on $80 is $16, so he gets back $96. The solution is $80.
Good problem! But I would also like to see your solution using the method of false position. Could you please add that (and let me know) for full marks on this post? Thanks.
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