题目

An old woman, having lost the use of her eyes, 61 (call) in a physician to heal them and made this bargain 62him in the presence of witnesses: that if he should cure her blindness, he should receive from her a sum of money; but 63her infirmity (弱视) remained, she should give him nothing. This agreement being made, the physician, time after time, applied his salve (药膏) to her eyes, and on every visit took something away, stealing all her property little by little. And when he had got 64she had, he healed her and demanded the 65(promise) payment. The old woman, when she recover已知钾玻璃的成分是·CaO·，若要制造5100kg的钾玻璃，通过计算求出需要各多少千克？