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Question 7 Charles and William salaries are in the ratio 5: 9. If both of their salaries are raised by RM 4200, then the proportion changes to 22: 27. Find William's salary. A. 8058.32 B. 9250.95 C. 7199.97 D. 13580.45 Points: 2​

Question 7 Charles and William salaries are in the ratio 5: 9. If both of their salaries-example-1
User Prit
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1 Answer

17 votes
17 votes

Answer: Choice C

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Work Shown:

  • c = salary for Charles before the raise
  • w = salary for William before the raise

Their salaries are in ratio 5:9 which means

c/w = 5/9

9c = 5w

w = 9c/5

w = 1.8c

Whatever Charles is earning, multiply by 1.8 to find how much William makes. This is before the raise of RM 4200.

After the raise for each person, then,

  • c+4200 = new salary for Charles
  • w+4200 = new salary for William

Their new salaries form the ratio 22:27, so,

(c+4200)/(w+4200) = 22/27

(c+4200)/(1.8c+4200) = 22/27

27(c+4200) = 22(1.8c+4200)

27c+113400 = 39.6c+92400

27c-39.6c = 92400-113400

-12.6c = -21000

c = -21000/(-12.6)

c = 1666.66666666667

c = 1666.67

Before the raise, Charles has a salary of RM 1666.67

Before the raise, William has a salary of w = 1.8c = 1.8*1666.67 = 3,000.006 which rounds to RM 3000.01

Add on 4200 to find William's salary after the raise.

3000.01+4200 = 7200.01

Unfortunately this isn't listed among the answer choices, but 7199.97 is fairly close. There's probably rounding error somewhere in my steps, or perhaps your professor made a rounding error. I'm not entirely sure.

In any event, it appears your teacher intends the answer is choice C.

User Jhonycage
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