MAths F.1

2007-03-19 2:26 am
a butcher sells beef at $20 per catty.a supermarket sells beef of the same quality at $16.50 per pound.given that 3 catties equal 4 pounds,which one sells beef at a lower price.
更新1:

2.anne typed 1000words at a speed of 30 words/min,and then typed 750words at a speed of 40 words/min.find her average typing speed.

更新2:

3.joe took 10 minutes to ride a bicycle from home to the shore.the average speed of the whole journey was 600m/min.if his speed in the last 1/3 of his journey was 500m/min. (a)find the time he took in the last 1/3 of his journey (B)find his speed in the remaining journey.

回答 (1)

2007-03-19 3:59 am
✔ 最佳答案
第1題:
money needed to buy 3 catties of beef in the butcher sells
=20*3=$60
money needed to buy 4 pounds of beef in the supermarket
=16.5*4=66

because 3 catties equal 4 pounds, the butcher sells beef at a lower price.

第2 題:
total time she used
=1000/30+750/40
=625/12 mins

total words she typed
=1000+750
=1750
average speed = words she typed/ time she used
= 1750/ (625/12)
= 33.6 words/min

第3題:
a) total distance= 600*10=6000m
first 1/3 of the journey = 6000/3 =2000m
time he took of the last 1/3 journey = 2000/500 =4mins

b)remaining distance= 6000-2000=4000m
time left=10-4=6mins
speed=4000/6=2000/3 (m/min)


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