Question 7th. If 4 lb. of Tea coft 1. 135. 4d, what will 4 Baggs coft, each Bag weighing 2 C. 39. 21 lb. at that Rate? When reduced the Stating will Atand thus: b: d. 1. s. d. If 4 400 1316: 131600 548:6:8 N. B. You may contract Questions in this Rule when 'you can divide the first and third Term by one Divifor, as in this Queftion, I divide them by 4, and then the Work will ftand thus. lb: d. :: If : 400 :: as before. fb : d. 1. s. d. 548:6: 8 Question Question 8th. If 108 Pounds in 12 Months gain 6 Pounds Intereft, how much will it gain in 7 Months? Anfwer, 3 l. 10 s. o d. For as 12 6 :: 7 : 3% 10s. o d. The Rule of Three Reverse S that by which we find, from three Numbers given, a fourth, in a reciprocal Proportion, inverted to the Proportion given. Obferving the Rule given in direct Proportion, it will be needless to say any thing more of it. EXAMPLES. Question ift. If 8 Men do a Piece of Work in 12 Days, how many Men muft there be to do the fame in 6 Days? Anfwer, 16 Men. D. M.: D. In this Queftion, I confider that the lefs Time, will require the more Men; fo I multiply the mid H dle dle Term by the greater Extream, and divide that Product by the lefs, and the Quotient is the Anfwer. Obferve this in all the following Questions. Question 2d. If 8 Men do a Piece of Work in 12 Days, in how many Days will 16 Men do the fame? Answer, 6 Days. m. :d. :: m. For if 8 12 :: 16 8. 16)96(6 Men the Answer. Question 3d. How many Yards of Canvas that is Ell wide, will line 20 Yards of Say three Quarters wide. Anfwer, 12. q. y. q. y. For if 3:20 5 12; for the wider the Cloth the lefs Number of Yards it requires. So if I x 20 by 3, and by 5. Question 4th. How many Foot of Matting of 2 Foot wide, will cover a Floor 20 Foot wide and 24 Foot long? Anfwer, 240 Foot. f.w. f.l. f.w. : f. 1. : For if 20: 24 :: 2 : 240 For the narrower the Matting, the more it will require; fo I multiply 20 by 24, and divide by 2. The Quotient is the Anfwer. Question 5th. If (according to the Statute) a right angled Paralelogram of 40 Perches in length, and 4 f in breadth, make an Acre of Land, how much in length must there be, when the breadth is 16 Perches? Anfwer 10 Perches. b. 1. For if 4 40 b. 1. Question 6th. If 12 Inches in length and 12 in breadth make a fuperficial Foot, how much muft there be in length when the breath is 4 Inches? Anfwer, 36 Inches long. i.l. i.b. i.b. i.l. For if 12 12 : :: 4 : 36 Question 7th. If one lend a Friend 640 Pounds 8 Months, what Sum muft he lend 12 Months to retaliate the former Favour? Answer, 4261. 13s. 4d. m. 1. m. For if 8 640 :: 12: 4261. 13s. 4 d. Question 8th. If one lends his Friend 600 Pounds 8 Months, how long muft he lend 400 Pounds to recompence the former Kindness? Anfwer, 12 Months. 1. m. m. Question 9th. If I have 1200 lb. Weight carried 36 Miles for 24 Shillings, how many Miles shall 1800 lb. Weight be carried for the fame Sum. Anfwer, 24 Miles. Ib. m. Ib. m. For if 1200 36 :: 1800: 24. Question 10th. If for 24 Shillings, I have 1200 lb. Weight carried 36 Miles, how many Pound Weight H 2 fhall fhall I have carried 24 Miles for the fame Money? Anfwer, 1800 lb. Weight. m. Ib. m. ib. For If 36 1200 :: 24: 1800 Question 11th. A General is befieged in a Town, in which are 1200 Soldiers, with Provifion for 3 Months; how many Men must he difmifs, that his Provifion may serve thofe that remains 8 Months? He must keep 450, and difmifs 750. For if 3 1200 :: 8: 450 Question 12th. If a Field will graze 21 Horfes 6 Weeks, how many will it graze 7 18 Horfes. Weeks? Answer, Question 13th. If a Field will graze 21 Horfes for 6 Weeks, how long will it graze 18 Horses? Answer, 7 Weeks. h. W. b. W. For if 21 6 :: 18 : 7 Question 14th. If 136 Mafons build a Fort in 28 Days, to preferve the Soldiers from the Enemy, but the General would have it built in 8 Days, how many Men must be set to Work? Anfwer, 476 Mafons. m. d. m. 136 :: 8: 476 d. For if 28 The |