[問題]天山03-02

[meimie]

Q2. Guy's net income equals his gross income minus his deductions. By what percent did Guy's net income change on January 1, 1989, when both his gross income and his deductions increased?

(1) Guy's gross income increased by 4 percent on January 1, 1989.
(2) Guy's deductions increased by 15 percent on Jabuary 1, 1989.

Ans:E (Statements 1 and 2 together are not sufficient)

請問為什麼不是C(Both statements together are sufficient, but neither statement alone is sufficient)呢?

[汪汪北鼻]

Gross income=1.04G
Deduction=1.15D

what percent of net imcome change= (1.04G-1.15D)-(G-D)/G-D

=0.04G-0.15D/G-D -->還是無法得知

[meimie]

Gross income=1.04G
Deduction=1.15D

what percent of net imcome change= (1.04G-1.15D)-(G-D)/G-D

=0.04G-0.15D/G-D -->還是無法得知

謝謝大大 :D