7. If 50% of (x-y)=30% of (x+y) then what percent of x is y?
A. 25%
B. 50%
C. 75%
D. 100%
ANS: A
EXPLANATION:
50/100 (X-Y) = 30/100 (X+Y)
1/2 (X-Y) = 3/10 (X+Y)
½ X - 3/10 X = 3/10 Y + 1/2 Y
2/10 X = 8/10 Y
Y = ¼ X
¼= 25%
8. 30 percent of a number is 15 less than 3/5th of a number. What is the number?
A. 48
B. 52
C. 50
D. 70
ANS: C
EXPLANATION:
30/100 X = 3/5 X – 15
3/10 X – 3/5 X = 15
3/10 X = 15
X = 50
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