Elementary arithmetic, with brief notices of its history... by Robert Potts.

21

5. If pure gold be worth ~4 per ounce and pure silver 5s., what
percentage of copper must be mixed with pure gold in order that the
value of a given quantity of the compound metal may be 15 times
that of an equal weight of a mixed metal containing 80 per cent. of
pure silver?
6. The denarius of the times of the Roman republic weighed 60 grains
of silver fine. Supposing a sestertium to be equivalent to 250 denarii,
and standard silver which is 3 7parts fine to be worth 5s. 2d. per ounce,
how much was a sestertium worth of our money?
7. A pound of silver is coined into 66 shillings, of which 62 only
are issued. If nineteen half-crowns and fifteen sixpences are melted
into bullion, and sent to the mint to be recoined, what sum will be
reissued?
8. A mass of metal being composed of fine gold 15 parts, silver 4
parts, and copper 3 parts, find how much of each is required in
making 18 cwt. of the composition.
9. The values of equal weights of gold and silver being ~23 3s. 10d.
and ~1 13s. respectively, compare the weights of a sovereign and of a
half-crown, if gold be valued at ~3 17s. 10ld. per ounce.
10. If 66 shillings weigh one pound Troy, how many shillings are
contained in one pound avoirdupois?
11. Allowing 441 guineas to weigh one pound Troy, and 32 halfpence to weigh one pound avoirdupois, what is the difference in grains
between the weights of a guinea and a halfpenny?
XXI.
1. Find the value of H- of one pound avoirdupois; and reduce
12oz. 8 drams to the fraction of a pound.
2. Reduce 7 of 3 of 15 cwt. to the fraction of - of a ton.
3. How much ironstone ore must be raised from a mine, that on
losing ~ in roasting, and -3 of the remainder in smelting, there may
result 506 tons of pure metal?
4. If a shekel contained 240 grains, what was the weight in
pounds avoirdupois of the head of Goliath's spear, which was 600
shekels of iron, and of his coat of mail, which consisted of 5,000 shekels
of brass (1 Sam. xvii. 5, 7)?
5. Find a sum of money which shall be the same part of ~61 9s. Id.
that 2cwt. 2qrs. lOlb. is of 36cwt. lqr.
6. Show that 21 times the price of one hundred weight in pounds
sterling is the price of one pound in pence. Ex. Let the price of one
hundred weight be ~14.
7. If a pound avoirdupois of copper is coined into 24 penny pieces,
and a pound Troy of standard silver into 66 shillings, standard silver
being a metal of which -- are pure silver and - copper, find the
value of one ounce of pure silver, if a pound avoirdupois contain 7,000
grains Troy.