Mathematical Aptitude - Ratio Proportion, Percentage and Discounting
- Option : B
- Explanation : Let Y’s salary = 100, then X’s salary = 50
X’s new salary = 50 × 3/2 = 75
Y’s new salary = 100 × 5/4 = 125
Combined old salary = 100 + 50 = 150
New combined salary = 75 + 125 = 200
Increase in combined salary = 50
Percentage increase = 50/150 × 100 = 33.33%
- Option : A
- Explanation : Let x water to be added to make water 20% of new
mixture.
Water in old mixture = 10% of 40 = 4 l
Water in new mixture to make it 20% = (4 + x) l
Now 20% of (40 + x) l = 4 + x
Solving equation, we get x = 5 l.
- Option : D
- Explanation : Let income = 100
New income = 120
New expenditure = 75 + 10% of 75 = 82.5%
New savings = 120 − 82.5 = 37.5
Old saving = 25,
Percentage increase in savings
= (37.5 − 25)/25 × 100
= 12.5/25 × 100 = 50%
- Option : D
- Explanation : Let C’s income = 100
B’s income = 100 + 20 = 120
A’s income = 125% of 120 = 150
Thus, A’s income is 50% higher than that of C.
- Option : C
- Explanation : Let cost price = 100
Net selling price = 100 + 8 = 108
Now 120 – (x% of 120) = 108
x = 10
