94 GANITASARASANGRAHA. Double Rule-of-three. The rule for arriving at (the value of) the interest which (operation) is of the nature of double rule-of-three :-- 4. The number representing the Iccha, 2 e., the amount the interest whereon is desired to be found out, is multiplied by the time connected with itself and is then multiplied by (the number representing) the (given) rate of interest for the given capital; (then the resulting product) is divided by the time and the capital quantity (connected with the rate of interest); this (quotient) is, in arithmetic, the interest of the desired amount. Examples in illustration thereof. 5. Purānas, 50, 60, and 70 (in amount) were dent out on interest at the rate of 3, 5 and 6 per cent (per mensem respect- ively); what is the interest for 6 months? 6. (A sum of) 30 karsäpanas and 8 panas werc lent out on interest at the rate of 74 per cent (per month); what is the interest produced in exactly 7 months ? 7. The interest on 60 for 2 months is seen to be 5 puranas with 3 punas; what would be the interest on 100 for 1 year? 8 The interest ,for 1 month and a half on lending out 150 is 15. What would be the interest obtained at this rate on 300 for 10 months? 9. A merchant lent out 63 karsāpanas at the rate of 8 for 108 (per month). What (is the interest) for 7 months ? The rule for finding out the capital lent out- 10. The capital quantity (involved in the rate of interest) is multiplied by the time connected with itself and is then divided rxtx I Tx0¹ 4. Symbolically=- where T, C and I are respectively the time, capital and interest of the pramana or the rate, and t, c and are respectively the time, capital and interest of the iccha. For an explanation of pramina, iccha, &c., see note under Ch. V. 2. 5. Unless otherwise mentioned, the rate of interest is for 1 month. 10. Symbolically CxTxi Ixt <= c.
