Page:The Rhind Mathematical Papyrus, Volume I.pdf/92

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76
CHAPTER I—EGYPTIAN ARITHMETIC
[34

Problem 34 A quantity, its 12, and its 14, added together, become 10. What is the quantity?

Multiply 11214 so as to get 10.

\ 1 11214
  2 312
\ 4 7
\ 17 [1]14
  14128 12
\ 1.

The total is the quantity required, 51217114.

Proof.

\ 1 51217114
\ 12 21214114128
\ 14 11418128156.

The whole numbers and simpler fractions (powers of 12) make a total of 91218, the remainder is 1418. The remaining fractions, namely,
17114128156
applied to 56, are equal to
844221,
making a total of 21, while 14 and 18 make 14 and 7, and so also a total of 21. Therefore the result obtained is correct.

The first step is a multiplication of the second kind (Introduction, page 5) with 11214. taken as multiplicand and 10 as product. After doubling twice, also taking )4 and doubling this twice, the author finds a combination of products exactly equal to 10, and it is not necessary for him to take the second and third steps that belong to this kind of multiplication when the product is.not obtained directly from the partial products. It is easy to see why this multiplication should be so simple; for we have already enough partial products to make any integer up to 14. Compare the notes to Problem 37.

SECTION VII

Problems 35-38. Division of a Hekat

In these problems in the papyrus the questions are put in a curious way: "I have gone a certain number of times into the hekat-measure, certain parts have been added to me, and I return filled. What is it that says this?" It is stated as if the vessel represented as speaking had gone

  1. See Introduction, page 5, footnote 2.