Explanation:

The best way to do this is to start with 100 and calculate the result.

The final number will be as follows:

[(100 × 1/6) ÷ 1/7] × 7/10

= (100/1) × (1/6) × (7/1) × (7/10)

= 245 /3 = 245/3%

So, the final number will be 245/3% of the original number.

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Explanation:

M is 35% of N, and L is 25% of N

So, M = 0.35N, and L = 0.25N.

To find out what percent L is of M, we need to evaluate:

(L/M) × 100% = (0.25N/0.35N) ×100% = (25/35) × 100% = 500/7%

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Explanation:

Let B’s salary be Rs. 100.

Then A’s salary = Rs. 125

Required percentage = [(125 – 100)/125] × 100 = (25 /125) × 100 = 20%

Thus, B's salary is lower than A's salary by 20%.

Hence, option (b) is correct.

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Explanation:

Principal (P) = Rs. 5000, Rate (r) = 12% per annum, Time (n) = 2 years

Compound Interest (C.I.) = [P {1 + (r/100)}n – P]

Simple Interest (S.I.) = (P × r × n)/100

Required difference = [P {1 + (r/100)}n – P] - (P × r × n)/100

= [5000 {1 + (12/100)}2 – 5000] – (5000 × 12 × 2)/100

= 5000 [(28/25) × (28/25) – 1] - 1200

= 5000 [(784 – 625)/625] - 1200 = 1272 – 1200 = Rs. 72

Thus, difference between simple interest and the compound interest for 2 years will be Rs. 72.

Hence, option (d) is correct.

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Explanation:

40% of the boys is same as half of the girls, and there are 20 girls.

So, 40% of boys = 20/2 = 10

Therefore, 100% of boys = (10/40%) × 100% = 25

Therefore, total number of boys = 25

Thus, total number of students = 25 + 20 = 45

Hence, option (b) is correct.

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Ans. (a) | Explanation:

Let distance between Delhi and Pune be A km.

Time taken by Sonali to reach Pune = 10 – 4 = 6 hours

Time taken by Priyanka to reach Delhi = 11 – 6 = 5 hours

Speed of train which leaves Delhi = A/6 km/hr

And Speed of train which leaves Pune = A/5 km/hr

Relative speed = A/6 + A/5 = 11A/30 km/hr

Distance covered by train which leaves Delhi in 2 hours = 2 × A/6 = A/3 km

Distance left to be covered = A – A/3 = 2A/3 km

Time taken by both the trains to cross each other = Distance left to be covered/ Relative speed = (2A/3)/(11A/30) = 20/11 hours = 1 hour 49 minutes

Required time = 6 pm + 1 hour 49 minutes = 7: 49 pm

Hence, option (a) is the correct answer.

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Ans. (c) | Explanation:

We know that, if we mix any liquid with water and sell it at cost price to gain a profit of x%, then the ratio of liquid and water is (100:x).

Here, x = 25%

Required ratio = 100:25 = 4:1

Hence, option (c) is the correct answer.

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Ans. (d) | Explanation:

In a month of 30 days beginning with Saturday, we will have 5 Saturdays, 5 Sundays and 20 Other days.

Visitors on 5 Saturdays = 640 × 5 = 3200

Visitors on 5 Sundays = 640 × 5 = 3200

Visitors on Other days = 310 × 20 = 6200

So, Total number of visitors in 30 days = 3200 + 3200 + 6200 = 12600

Average number of visitors per day = 12600/30 = 420

Hence, option (d) is the correct answer.

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Ans. (d) | Explanation:

Number of Vaccinations done in Lucknow in all the three months = 85 + 45 + 90 = 220

Average number of Vaccinations done in Lucknow = 220/3

Number of Vaccinations done in Jhansi in all the three months = 30 + 50 + 60 = 140

Average number of vaccinations done in Jhansi = 140/3

Required Percentage = {(220/3)/(140/3)} × 100

= (220/140) × 100

= 157.14% (approx.)

Hence, option (d) is the correct answer.

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Ans. (d) | Explanation:

Ratio of glycer and alcohol in the mixture = 20 : 80 = 1 : 4

So, Quantity of glycer in the solution = 176 × 1/(1 + 4) = 35.2 ltr

So, quantity of alcohol in the solution = 176 – 35.2 = 140.8 ltr

In the final mixture, alcohol is 60% and glycol is 40%.

40% corresponds to 35.2 litres.

60% corresponds to 35.2 × (60%/40%) = 52.8 litres.

So, Quantity of alcohol that should be evaporated = 140.8 litr – 52.8 ltr = 88 ltr

Hence, option (b) is the correct answer.

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