CBSE Class 7 Mathematics Percentage MCQs Set 11

Answer: (d) 125%

Explanation:
1. The ratio 5 : 4 is the fraction \( \frac54 \).
2. \( \frac54\times100=125 \), so it is 125%.

Teacher's Note:
1. To change a fraction or ratio to a percent, multiply by 100.
2. A ratio with the first term larger than the second is more than 100%.

Answer: (d) 350%

Explanation:
1. Multiply the number by 100: 3.5 × 100 = 350.
2. So 3.5 = 350%.

Teacher's Note:
1. Any number x equals (100x)%.
2. A number greater than 1 is always more than 100%.

Answer: (a) 0.005

Explanation:
1. Half of 1% is 0.5%.
2. \( 0.5\%=\frac{0.5}{100}=0.005 \).

Teacher's Note:
1. Divide the percent by 100 to get a decimal.
2. 0.5 divided by 100 moves the decimal point two places left.

Answer: (d) Rs. 5.10

Explanation:
1. \( \frac{15}{100}\times34=5.1 \).
2. So the answer is Rs. 5.10.

Teacher's Note:
1. x% of N means (x/100) × N.
2. 10% of 34 is 3.40 and 5% is 1.70; adding gives 5.10.

Answer: (a) 2.25

Explanation:
1. \( 3\frac47=\frac{25}{7} \).
2. \( \frac{63}{100}\times\frac{25}{7}=\frac{9\times25}{100}=2.25 \).

Teacher's Note:
1. Convert the mixed number to an improper fraction first.
2. 63 is a multiple of 7, so the 7 cancels neatly.

Answer: (c) 860

Explanation:
1. 860% of 50 = 8.6 × 50 = 430.
2. 50% of 860 = 430.
3. Sum = 430 + 430 = 860.

Teacher's Note:
1. x% of y equals y% of x, so both terms here are equal.
2. Each term is 430, so the sum is double that.

Answer: (b) 0.25%

Explanation:
1. Convert 7.2 kg to grams: 7.2 × 1000 = 7200 g.
2. \( \frac{18}{7200}\times100=0.25 \).

Teacher's Note:
1. Bring both quantities to the same unit before taking the ratio.
2. 18/7200 = 1/400 = 0.25%.

Answer: (c) 10

Explanation:
1. \( \frac{0.01}{0.1}\times100=0.1\times100=10 \).

Teacher's Note:
1. Divide the part by the whole, then multiply by 100.
2. 0.01 is one tenth of 0.1, and one tenth is 10%.

Answer: (b) 75%

Explanation:
1. \( \frac{1987.5}{2650}\times100=75 \).

Teacher's Note:
1. Percent = (part ÷ whole) × 100.
2. 1987.5 = 0.75 × 2650, which is three quarters.

Answer: (c) 1.6

Explanation:
1. Pure acid = 20% of 8 litres.
2. \( \frac{20}{100}\times8=1.6 \) litres.

Teacher's Note:
1. The percentage of a solution is taken on its total volume.
2. 20% is one fifth, and one fifth of 8 is 1.6.

Answer: (a) Rs. 6876.10

Explanation:
1. Price after rebate = 6650 × 0.94 = Rs. 6251.
2. Sales tax is charged on the reduced price: 6251 × 1.10 = Rs. 6876.10.

Teacher's Note:
1. A rebate lowers the price and sales tax raises it; apply them one after the other.
2. Multiplying by 0.94 and then by 1.10 does both steps at once.

Answer: (c) Rs. 20

Explanation:
1. 25% of 1600 = 400.
2. 5% of 400 = Rs. 20.

Teacher's Note:
1. Work from the inside bracket outwards.
2. Equivalently, 5% × 25% = 1.25%, and 1.25% of 1600 = 20.

Answer: (b) 0.0625

Explanation:
1. \( 0.25\times0.25=0.0625 \).

Teacher's Note:
1. Convert each percent to a decimal before multiplying.
2. 25% of 25% is one quarter of one quarter, which is 1/16.

Answer: (a) 36

Explanation:
1. \( \frac{129.6}{360}\times100=36 \).

Teacher's Note:
1. Divide the part by the whole and multiply by 100.
2. 129.6/360 = 0.36.

Answer: (b) 130

Explanation:
1. 20% of 422.50 = 84.5.
2. Let the number be x: 0.65x = 84.5, so x = 84.5/0.65 = 130.

Teacher's Note:
1. Evaluate the known side first, then solve the simple equation.
2. Check: 65% of 130 = 84.5.