[問題]PREP-T2-Q136 Q149

[oneseven]

Q136
A school purchased 2 computers whose prices were $1,000 and $2,000, respectively. The school is to purchase 2 more computers from a list of computers whose prices rang from $1,000 to $2,000, inclusive. The greatest possible average (arithmetic mean) price of the 4 computers is how much greater than the least average price of the 4 computers?

(A) $250
(B) $500
(C) $750
(D) $1,000
(E) $1,250

Answer : B

Q149
To determine her state income tax last year, Elena computed 5 percent of her gross income, rounded the resulting figure down to the nearest $100, and $50 for each dependent that she claimed. If Elena's gross income was $34,500 and she claimed 2 dependents, how much did she determine her state income tax to be?

(A) $1,600
(B) $1,625
(C) $1,650
(D) $1,675
(E) $1,700

Answer : A
請教如何算 謝謝

[hey]

Q136:

(2000*3+1000)/4-(2000+1000*3)/4=1750-1250=500

Q149你的題目少了幾個重點關鍵字, 正確的題目是:
To determine her state income tax last year, Elena computed 5 percent of her gross income, rounded the resulting figure down to the nearest $100, and subtracted $50 for each dependent that she claimed, If elena's gross income was $34500 and she claimed 2 dependents, how much did she determine her state income tax to be?

down to the nearest $100:四捨五入到$100
34500*5%=1725 (the nearest $100 will be 1700)
1700-50*2=1600

[oneseven]

感謝 ...原來是漏了關鍵字呀

[chiungfen]

Q136:

(2000*3+1000)/4-(2000+1000*3)/4=1750-1250=500

高人指點的此算式，我不太了解，可以有人為我解圍一下嗎?


我的思路是(1000+1000+1000)/4=750
(2000+2000+2000)/4=1250


兩個算式相減 得500
請更正思路