Page:The Rhind Mathematical Papyrus, Volume I.pdf/85

28] Multiply 3 by 4.

Problem 27

''A quantity and its $1/undefined$, added together become 21. What is the quantity?''

Assume 5.

As many times as 6 must be multiplied to give 21, so many times 5 must be multiplied to give the required number.

Problem 28

''A quantity and its 35 are added together and from the sum $1/undefined$ of the sum is subtracted, and 10 remains. What is the quantity?''

Subtract from 10 its $1/undefined$, which is 1. The remainder is 9. This is the quantity; its $1/undefined$, 6, added to 9, makes 15, and $1/undefined$ of 15, taken away from 15, leaves 10. Do it thus. . ..