-
lotrgandalf
- Junior | Next Rank: 30 Posts
- Posts: 16
- Joined: Sat May 30, 2015 9:36 am
Smart numbers can be picked if no amounts are given in the problem; when any amount or total is given don't pick smart numbers.
What am I doing wrong by choosing a smart number for gross and deduction
I solved OG 13, DS Q55 in the following way
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 January 1, 1989.
Solution: Choose smart number for Gross(200) and Deduction(100).
old change new
--------------------------------------------
Net |300 | x |323
Gross |200 | 8 |208
Deduction |100 | 15 |115
therefore, x = 323-300/300. Hence (C).
But the correct answer is (E). I can solve this problem by forming algebraic equations, but why I can't use a smart number here?
What am I doing wrong by choosing a smart number for gross and deduction
I solved OG 13, DS Q55 in the following way
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 January 1, 1989.
Solution: Choose smart number for Gross(200) and Deduction(100).
old change new
--------------------------------------------
Net |300 | x |323
Gross |200 | 8 |208
Deduction |100 | 15 |115
therefore, x = 323-300/300. Hence (C).
But the correct answer is (E). I can solve this problem by forming algebraic equations, but why I can't use a smart number here?
