HELP~數學questions...15 marks

2008-08-27 11:23 pm

(a) Given that V=4÷3πr^3, find the value of V when π = 22÷7 and r = 21.

(b) Given that A= P(1+r÷100), find the value of A when P=8000 and r= 10.

(c) A man buys a eggs at $3m each and sells them at $(n-5m) each. After he
has sold all the eggs, how much did he gain?

(d) A and B are two consecutive numbers (B<A). Halfg of B exceeds
one-fourth of A by 1, find the values of A and B.

更新1:

A man buys "r" eggs at $3m each and sells them at $(n-5m) each. After he has sold all the eggs, how much did he gain? a is a unknown number, so I change to "r".

回答 (1)

Pui Tak

2008-08-28 2:53 am

✔ 最佳答案

1.)
V=4÷3πr^3
when π = 22÷7 and r = 21
V=4/3(22/7)21^3
V=4/87318
V=2/43659

2.)
A= P(1+r÷100)
when A when P=8000 and r= 10
A=8000(1+10/100)
A=8000*1.1
A=8800

3.)
I'm sorry, the information you gave is not enough, it is because we don't know how many eggs that he had bought

4.)
(1/2)B-(1/4)A =1
when A=B+1
(1/2)B-(1/4)(B+1)=1
0.5B-0.25B-0.25=1
0.25B=1.25
B=5
Therefore, B is 5 while A=5+1=6

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