Take a piece of cardboard 13 inches long and 5 wide, thus giving a
surface of 65 inches. Cut this strip diagonally, giving two pieces
in the shape of a triangle, and measure exactly 5 inches from the
larger end of each strip and cut in two pieces. Take these strips and
put them into the shape of an exact square, and it will appear to be
just 8 inches each way, or 64 inches--a loss of one square inch of
superficial measurement with no diminution of surface.
[Illustration: 5 × 13 = 65 square inches.]
49. If we buy 20 sheep for 20 shillings, and give 2s. for wethers,
1s. 6d. for ewes, and 4d. for lambs, how many of each must we buy?
50. A sets out from a place and travels 5 miles an hour. B sets out
4½ hours after A and travels in the same direction 3 miles in the
first hour, 3½ miles the second hour, 4 miles the third hour, and
so on. In how many hours will B overtake A?