F.3 Maths about percentage change!!!!!!!!!!plz help``

2008-11-04 2:52 am

呢題唔識做,搵人幫幫手,唔該!!

Simon is a salesman of audio and video products. His monthly salary ($ I )
is the sum of basic salary ($ B ) and commission which is equal to 1/10 of
the sales amount ($ S ) of that month, i.e.

I = B + 1/10 x S

(a) Last year, Simon's basic salary was $ 4 000 and the sales amount in
December was $ 130 000. Find his salary in last December.

(b) This year Simon's basic salary increases by 5%. Sales amount in January
was decreased by 8% as compared to last month. What was the percentage
change of Simon's monthly salary from last December to this January?
(Give the answer correct to the nearest 0.1%)

要步驟的,THX =]

回答 (1)

Marco

2008-11-04 3:11 am

✔ 最佳答案

a) B=4 000 , S=130 000
so I = 4000 + 1/10(130 000)
= 4000 + 13 000
=17000
so his salary in last December is $17000.

b) B in January = 4000 x (1-5%)
= 4000 x 95%
= 3800
S in January = 130 000 x (1-8%) x (1/10)
= 130 000 x 92% x (1/10)
= 119600 x (1/10)
= 11960
I in January = B + S
= 3800 + 11960
= 15760

percentage change of Simon's monthly salary from
last December to this January：
= (I in January / I in December) x 100%
= (15760/17000) x 100%
=92.7%

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