test is coming , who can help?

Ball

2008-11-19 2:03 am

9) It costs a manufacturer X dollars per component to make the first 1,000 components. All subsequent components cost X÷3 each. When X = $1.50 How much will it cost to manufacture 4,000 components?

A B C D E
$3,500 $3,000 $4,000 $3,250 $4,500
10) A train traveling at 60 mph enters a tunnel that is 5 miles long. The train is one mile long. How many minutes does it take for the whole train to pass through the tunnel?
ABCDE
741056

11)In the Shelbyville election, the Republican candidate received one and a half times as many votes as the Democrat candidate. The Democrat candidate received one third more votes than the Independent candidate. 900 votes were cast for the Independent candidate. How many votes were cast for the Republican candidate?
A B C D E
9001,400 1,600 1,000 1,800

12)Anna and John both drive to their new home 400 miles away. Anna drives the family car at an average speed of 60 mph. John drives the removal truck at an average speed of 50 mph. During the journey, Anna stops for a total of 1 hour and 20 minutes, John stops for half as long. What is the difference in minutes between their arrival times?
A B C D E
60 55 40 90 80

回答 (1)

Uncle Michael

2008-11-19 7:12 am

✔ 最佳答案

9)
The answer is B ($3000).

Cost of the first 1000 components
= 1000X
= 1000*($1.5)
= $1500

Cost of the rest 3000 components
= 3000(X/3)
= 1000X
= $1500

Total cost
= $1500 + $1500
= $3000

=====
10)
The answer is E (6).

Total distance for the whole train to pass through the tunnel
= (5 + 1) miles
= 6 miles

Speed
= 60 miles/h
= (60 miles)/(60 min)
= 1 mile/min

Time taken
= (6/1) min
= 6 min

=====
11)
The answer is E (1800).

Votes that cast for the Independent candidate
= 900 votes

Votes that cast for the Democrat candidate
= 900 x [1 + (1/3)] votes
= 900 x (4/3) votes
= 1200 votes

Votes that cast for the Republican candidate
= 1200 x [1 + (1/2)] votes
= 1200 x (3/2) votes
= 1800 votes

=====
12)
The answer is C (40).

Time taken by Anna
= [(400/60) + (1+20/60)] h
= [(6 + 40/60) + (1 + 20/60)] h
= 8 h
= 480 min

Time taken by John
= [400/50 + (1 + 20/60)] h
= [8 + 40/60] h
= 520 min

Difference
= (520 - 480) min
= 40 min
=

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