131. In the year 2005, the car industry had two car manufacturers – Maruti and Mahindra with market shares of 25% and 75% respectively. In year 2006, the overall market for the product increased by 50% and a new player Audi entered the market and captured 15% of the market share. If share of maruti increased to 50% in the second year, then what was the share of Mahindra in that year ?
Sol:-
According to question,
New market share in 2006 = 100 + 100 × 50%
= 150
Maruti share in 2006 = 25 + 25 × 50%
= 37.5
∴ % share of Mahindra = \(\frac{{90}}{{150}} \times 100\) = 60% Answer
132. Ankit, a businessman, earned a profit of 50% and donated 50% of total capital (initial capital + profit) in the first year. The same course was followed in the 2ⁿᵈ year and 3ʳᵈ year. If he is left with 14445 Rs, then find amount donated by Ankit at the end of second year.
Sol:-
Let the initial capital of the businessman = 100
∴ profit = 100 × 50%
= 50
total capital = 100 + 50 = 150
∴ Donation given = 150 × 50% = 75
∴ Capital for the 2ⁿᵈ year = 16 × 535 = 8560
Donation for the 2ⁿᵈ year = 9 × 535 = 4815 Answer
133. A fraction is such that if the double of the numerator and the triple of the denominator is changed by +10% and -10% respectively then we get 121% of \( \boldsymbol{\frac{{100}}{{27}}} \). Find the fraction.
Sol:-
Let fraction = \(\frac{x}{y}\)
⟹ \(\frac{{2x}}{{3y}} \times \frac{{110}}{{90}} = \frac{{121}}{{100}} \times \frac{{100}}{{27}}\)
\(\frac{{2x}}{{3y}} = \frac{{121}}{{27}} \times \frac{9}{{11}}\)
\(\frac{x}{y} = \frac{{11}}{2}\)
∴ required fraction is \( \boldsymbol{\frac{{11}}{2}} \) Answer
134. The hourly wages of a labour are increased by \( \boldsymbol{12\frac{1}{2}} \)% wheareas the weekly working hours are reduced by 8%. Find the % change in the weekly wages if she was getting Rs. 1500 per week for 60 hours previously.
Sol:-
\(12\frac{1}{2}\)% = \(\frac{1}{8}\) ↑ 8% = \(\frac{2}{{25}}\) ↓
Using successive method net % change = 12.5 – 8 – \(\frac{{12.5 \times 8}}{{100}}\)
= 3.5% Answer
Alternatively:
135. If salary of a person is increased by Rs. 50000 and the rate of tax is decreased by 2% from 12% to 10%. If in both the cases 28% of the income is tax free then find the increased salary.
Sol:-
Let the initial salary of the person = x
∴ (x + 50000)×10% = x × 12%
(x + 50000) × 5 = 6x
∴ x = 25000 Answer
136. Price of a commodity is first increased by y% and then decreased by y%. If the new price is \( \boldsymbol{\frac{M}{{100}}} \), find the original price.
Sol:-
net % change = y – y – \(\frac{{{y^2}}}{{100}}\)
= \( – \frac{{{y^2}}}{{100}}\)%
Let original price = x
∴ x – \(\frac{{x{y^2}}}{{100}} \times \frac{1}{{100}}\) = \(\frac{M}{{100}}\)
x(100² – y²) = 100M
∴ x = \( \boldsymbol{\frac{{100M}}{{{{100}^2} – {y^2}}}} \) Answer
137. The ratio of Amit’s salary for January to his salary for february was 1.5 : 1.333 and the ratio of the salary of february to that for march was 2 : 2.6666. The worker got 30 rupees more for march than for january and received a bonus consituting 30% of the salary of three months. Find the bonus.
Sol:-
bonus = (27 + 24 + 32) × 6 × 30%
= 194.4 Answer
138. A’s salary is first increased by 10% and then decreased by 20%. The result is same as B’s salary increased by 20% and reduced by 10%. Find the ratio of B’s salary to that of A’s.
Sol:-
\(A\left( {1 + \frac{{10}}{{100}}} \right)\left( {1 – \frac{{20}}{{100}}} \right) = B\left( {1 + \frac{{20}}{{100}}} \right)\left( {1 – \frac{{10}}{{100}}} \right)\)
A × 110 × 80 = B × 120 × 90
A × 88 = B × 108
∴ \( \boldsymbol{\frac{B}{A} = \frac{{22}}{{27}}} \) Answer
139. 10% of delhi’s population migrated to mumbai, 10% of the remaining migrated to Goa and 10% of the rest migratef to calcutta. If the male population, which was left in Delhi, remained only 437400, find the population of Delhi city before the migration and its effects if it is given that before the migration the male population was half the female population and this did not change after migration.
Sol:-
Before migration \(\frac{{male}}{{female}} = \frac{1}{2}\)
it is same as after migration \(\frac{{male}}{{female}} = \frac{1}{2}\)
∴ Number of male after migration = \(\frac{1}{{(1 + 2)}}\) × 729 = 243
& 243 ⟶ 437400
1 ⟶ 1800
∴ initial population = 1000 unit = 1000 × 1800
= 1800000 Answer
140. To pass an examination 40% marks are essential. A obtained 20% less marks than the pass marks and B obtained 25% marks less than A. What percent less than sum of A’s and B’s marks should C obtain to pass the exam ?
Sol:-
Let the total marks in the examination = 100
∴ pass marks = 100 × 40% = 40
marks obtained by A = 40 × 80% = 32
marks obtained by B = 32 × 75% = 24
∴ combined marks obtained by A + B = 32 + 24 = 56
∴ required marks for C to pass the exam = 56 – 40 = 16
∴ % marks for C = \(\frac{{16}}{{56}} \times 100\) = \( \boldsymbol{28\frac{4}{7}\%} \) Answer