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Civil Service Commission Professional or Sub-Professional Reviewer - Page 81/159

Mathematics Test III Solution - Page 81

Solutions

1. If 9x - 7 = 18y then  9x - 7  = ________?
                                       6

9x - 7 = 18y

 9x - 7  =  18y 
    6            6

= 3y *Ans.

2. A student buys an MSA Reviewer Book for $175 after receiving a discount of 12.5%. What was the marked price?

1 MP - 0.125 MP = $175

0.875 MP = $175

7/8 MP = $175 (note : 7/8 is the fraction form of 0.875)

MP = $175 x (8/7)

MP = $200 *Ans.

3. A town house unit was sold fir $2.50 M, yielding a 25% profit. For how much would it be sold to yield only a 10% profit on the cost?

Let C be the original cost of the house
Let 0.25C be the profit

C + 0.25C = $2.5 M

1.25C = $2.5M

 1.25C  =  $2.5M 
 1.25          1.25

C = $2M

The new selling price that would yield at 10% profit on the cost would be :

= $2M + 0.10 ($2M)
= $2M + 0.20M
= $2.2M *Ans.

4. What single discount is equivalent to successive discounts if 5% and 10%?

The formula for a single rate of discount equivalent to the series of discounts is :

R = 1 - [(1 - r1) (1 - r2)...(1 - rn)]

for r1 = 5% and r2 = 10%

R = 1 - [(1 - 0.05) (1 - 0.10)]
    = 1 - [(0.95) (0.90)]
    = 1 - 0.855
    = 0.145 or 14.5% *Ans.

5. How many miles are there in 40 kilometers?

1 mile = 1.6 kilometers

40 kilometers = 40 km x  1 mile 
                                      1.6 km

                      = 25 miles *Ans.

Civil Service Reviewer Post 81/159