154.
When the gardener found that he would have 150 too few if he set his posts a foot apart, and seventy to spare if he set them at every yard, he had 180 posts.
155.
In order to buy with £100 a hundred animals, cows at £5, sheep at £1, and geese at 1s. each, the purchaser must secure nineteen cows, one sheep, and eighty geese.
156.
If John, who is 21, is twice as old as Mary was when he was as old as Mary is, Mary’s age now is 153⁄4 years.