CRE 2 - Percentage Change

Percentage increase = $\frac{Final value - Initial value}{Initial value}\times 100\%$ = $\frac{5100-4200}{4200}\times 100\%$ = 21.42 = approx 21%

Hence, option (e).

Let the number be N.

Number increases by 40 due to 20% of itself.

⇒ 20% of N = 40

⇒ 20/100 × N = 40

⇒ N = 200.

Hence, option (a).

Let x be the unknown positive number. Then, correct answer = 6x

Wrong answer = x/6

Error = 6x – x/6 = 35x/6

With respect to correct answer, % error can be found as, $\frac{{\displaystyle \frac{35x}{6}}}{6x}\times 100$ = $\frac{35x}{36x}\times 100$ = 97%

Hence, option (b).

Let aggregate score be M and pass marks be x.

Then, by conditions of the problem, 0.3M = x – 50,

and, 0.45M = x + 25

Solving these simultaneous equations we get x = 200 marks

Hence, option (b).

Let the third number be x

Then, first number = 0.5x and second number = 0.4x

Second number is less than first by (0.5x – 0.4x) i.e. 0.1x

In terms of %age: 0.1x/0.5x × 100 = 20%

Hence, option (b).

Let total marks = x

∴ Pass marks = 40% of x

Also pass marks = 240 + 40 = 280

∴ 40% of x = 280

x = 280/(40%) = 700

Hence, option (a).

Let the earnings of C be 'c'.

⇒ Earnings of A = 25% less than earnings of C = 3/4 × c

⇒ Earnings of A = 20% more than earnings of B
⇒ 3/4 × c = 6/5 × earnings of B
⇒ Earnings of B = 5/8 × c

Givne, c - 5/8 × c = 900
⇒ 3/8 × c = 900
⇒ c = 2400

Hence, option (d).

Let the capacity of tank be C liters

Then, 0.95 C = 38 liters

∴ C = 38/0.95 = 40 liters

Now, (40 - 38=) 2 liters of petrol must be poured to fill the tank.

Hence, option (d).

Let x lakh tones wheat is produced in the country.

When 17% of it is lost in grinding, the country needs to import 6 lakhs tonnes.

⇒ Consumption of wheat (in lakh tones) = 0.83x + 6   ...(1)

When 5% of it is lost in grinding, the country does not need to import.

⇒ Consumption of wheat = 0.95x   ...(2)

From (1) and (2)

0.83x + 6 = 0.95x

⇒ 0.12x = 6 or

x = 50 lakh tonnes = 50,00,000 tonnes

Alternately,
Due to saving (17 - 5 = ) 12% of wheat produced, the country need not import 6 lakh tones of wheat.

⇒ 12% of Wheat produced = 6 lakh tones

⇒ 12/100 × Wheat produced = 6 lakh tones

⇒ Wheat produced = 50 lakh tones

Hence, option (d).

After 20% increase, men = 3000 × 1.2 = 3600

After 40% decrease, women = 3000 × 0.6 = 1800

So women as a percentage of men =1800/3600 × 100 = 50%

Hence, option (a).

If 60% is flour, 20% is sugar. So ghee = (100 - 60 - 20) = 20%.

So quantity of ghee in 2 kg laddoos = 20% of 2000 gms = 400 gms.

Hence, option (a).

A’s income = 1.50 of B’s income = 3/2 × B’s income

B’s income = 2/3 of A’s income = 66.66% of A’s income.

Hence, option (a).

Let the original fraction = x/y

∴ $\frac{x+50\% of x}{y - 20\% of y}=\frac{3}{10}$

⇒ $\frac{1.5x}{0.8y}=\frac{3}{10}$

⇒ x/y = 4/25

Hence, option (e).