數學能人請進=v= 一道英語數學題~

1. (a) What marks does Emmy get?

Solution:
6A+5B+1C+8D = 6 x 5 + 5 x 2 + 1 x (-1) + 8 x (-4)
= 7


1. (b) What marks does Pansy get?

Solution:
7A+4B+9D = 7 x 5 + 4 x 2 + 9 x (-4)
= 7

(c)It is known that the choices of Karen are different from those of Emmy and Pansy. If Karen gets 7 marks, what are her possible choices?

Solution:
i) 5A,6B,2C,7D
ii) 4A,7B,3C,6D
iii) 3A,8B,4C,5D
iv) 2A,9B,5C,4D
v) 1A,10B,6C,3D
vi) 11B,7C,2D


A stone fell from a slope into a lake. The following table records the location of the stone from the lake at different times, in which the positive numbers the location above the water level of the lake, and the negative numbers represent the location below the water level. It is known that the stone located at 35m above the water level of the lake initially.

有一塊可頭由斜坡滾下湖,以下的圓表紀錄了那些石頭在不同時間滾下湖裡的位置,正數代表石頭位置高於湖水水面,負數代表石頭位置低於湖水水面。已知石頭原來位於高於湖水水面35米高的地方。