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

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inhabitants of the earth, supposing, according to our present knowledge, the most probable value of the sun's mean distance from the
earth to be 91,713,000 miles, and that light from the sun reaches the
earth in 8min. 18sec.?
XXXI.
1. Shew that, in the year 1850, 7 times the number of days
preceding June 18 were equal to 6 times the number following that
date.
2. How many days were there from 10 January to 4 May, 1872,
both days included?
3. If a father died in 1873 at the age of 96, and his son died in
1860 aged 50, how old was the father when the son was born?
4. If on Dec. 25, 1870, a man's age is 30000 days, find the day and
year of his birth.
5. In the year 1873 a man was 75 years old, and 25 years ago he
was twice as old as his son; what was his son's age in 1874?
6. If A be 10 years younger than B, and 5 years older than C
in the year 1860; if C were 25 years old 15 years ago, when will B be
60 years old?
7. If the Easter term at Cambridge commences on a WVednesday
and ends on a Friday, shew that it divides either on a Thursday at
noon, or on a Sunday at midnight. In 1855, the Easter term began
on Wednesday, 18 April, and ended on Friday, 6 July.
8. In the year 1860, the first day of January was a Sunday; find
the next two years in which this will happen again.
9. There was a full moon on June 26, 1858, at 9hrs. 13min. a.m.
The interval between successive full moons has since been on the
average 29d. 12hrs. 47min. 30sec.; how many full moons happened
until Dec. 31, 1873, and when did the last take place within that
period?
10. The Times newspaper of Monday, 14 February, 1876, bears
the number 28551. Supposing the paper to have been published
every week day without intermission and numbered consecutively,
give the day of the week, month, and year when No. 1 was published.