If, with marbles in two pockets, I add one to those in that on the right, and then multiply its contents by the number it held at first, and after dealing in a similar way with those on the left, find the difference between the two results to be 90; while if I multiply the sum of the two original quantities by the square of their difference the result is 176, I started with twenty-three in the right-hand pocket and twenty-one in the other.
75.
The circle of twenty-one friends who arranged to meet each week five at a time for Bridge so long as exactly the same party did not meet more than once, and who wished to hire a central room for this purpose, would need it for no less than 20,349 weeks, or more than 390 years, to carry out their plan.
76.
If a herring and a half costs (not cost) a penny and a half, the price of a dozen such quantities is eighteenpence.
77.
The sum of money which in a sense appears to be the double of itself is 1s. 10d., for we may write it one and ten pence or two and twenty pence.