Chamberlain's Arithmetick being a plain and easie explanation of the most useful and necessary art of arithmetick in whole numbers and fractions, that the meanest capacity may obtain the knowledge thereof in a very short time : whereunto are added many rules and tables of interest, rebate, purchases, gaging of cask, and extraction of the square and cube roots / composed by Robert Chamberlain, accomptant and practitioner in the mathematicks.

Example.

In the foregoing Example where 300 l. is to be paid at 3 Months, 300 l. more at 6 Months, and 300 l. more at 9 Months, it is found out by the said Operation that 6 Months is the exact time for payment of the whole Sum of 900 l. To prove this, there was 300 l. to be paid at 3 Months, but is not paid unto 6 Months, which is 3 Months longer, and the Interest of 300l. for 3 Months at 6 l. per Cent. is 4 l. 10 s.

The 300 l. paid at 6 Months is the time equated or found out.

The other 300 l. to be paid at 9 Months is to be now paid at 6 Months, which is 3 Months before his time of Payment, the Interest whereof for 3 Months is 4 l. 10 s. as before, therefore 6 Months is the exact time for payment of the whole Sum of 900 l.

A Merchant oweth 750 l. to be paid at 4 several payments; 200 l. at 4 Months; 250 l. more at 8 Months, 150 l. more to be paid at 10 Months, and 150 l. more at 12 Months. I require to know what time the whole 750 l. ought to be paid in,

that neither Debtor nor Creditor may be losers?

l.	l.
200 multiplied by 4 Months is	800
250 multiplied by 8 Months is	2000
150 multiplied by 10 Months is	1500
150 multiplied by 12 Months is	1800
	6100

〈 math 〉〈 math 〉

The several Sums of payment being multiplied by their respective time, the Sum of their Products is 6100, which divided by 750, the Quotient gives eight Months and 2/15 for the time of payment altogether.

There is owing to a Merchant 480 l. to be paid 120 l. ready mony, 120 l. at four Months, 120 l. more at eight Months, and 120 l. more at 12 Months. I demand the exact time for payment of the whole Sum 480 l. so that neither Debtor nor

Creditor may have any advantage nor be damnified.

l.	l.
120 multiplied by 0 Months is	000
120 multiplied by 4 Months is	480
120 multiplied by 8 Months is	960
120 multiplied by 12 Months is	1440
	2880

〈 math 〉〈 math 〉

The several Products added together make 2880, which divided by the whole Sum 480 l. the Quotient giveth 6 Months, as was required.