The DAV Books Solutions Class 5 Maths and **DAV Class 5 Maths Chapter 12 Brain Teasers** Solutions of Percentage offer comprehensive answers to textbook questions.

## DAV Class 5 Maths Ch 12 Brain Teasers Solutions

Question 1.

Tick (✓) the correct answer.

(a) 10% of 74.6 is-

(i) 4.6

(ii) 7.4

(iii) 7.46

(iv) 746

Solution:

\(\frac{10}{100}\) of 74.6 = \(\frac{10}{100}\) × 74.6 = 7.46

So, option (iii) is correct.

(b) 8 tenths = ______%

(i) 8

(ii) 80

(iii) 0.8

(iv) 0.08

Solution:

8 tenth = (\(\frac{8}{10}\) × 100)% = 80%

So, option (ii) is correct.

(c) 33\(\frac{1}{3}\)% of 10% of 600 litres = ______ litres.

(i) 20

(ii) 120

(iii) 200

(iv) 220

Solution:

33\(\frac{1}{3}\)% of 10% of 600 l

= \(\frac{100}{3}\)% × 10% × 600 l

= \(\frac{100}{3} \times \frac{1}{100} \times \frac{10}{100}\) × 600 l

= 20 l

So, option (i) is correct.

(d) The percentage of shaded part in the given figure is-

(i) 80%

(ii) 70%

(iii) 75%

(iv) 85%

Solution:

\(\frac{3}{4}\) = (\(\frac{3}{4}\) × 100)% = 75%

So, option (iii) is correct.

(e) Jack went up the hill and came down with a bucket three-fifth filled with water. Then the percentage of water left to be filled in the bucket is-

(i) 60%

(ii) 30%

(iii) 40%

(iv) 50%

Solution:

\(\frac{3}{5}\) = (\(\frac{3}{5}\) × 100)%

= (3 × 20)%

= 60%

% of water left to be filled = (100 – 60)% = 40%

So, option (iii) is correct.

Question 2.

Write each of the following as a percentage.

(a) 7 tenths

Solution:

7 tenths = (\(\frac{7}{10}\) × 100)% = 70%

(b) \(\frac{328}{100}\)

Solution:

\(\frac{328}{100}\) = (\(\frac{328}{100}\) × 100)% = 328%

(c) 0.07

Solution:

0.07 = (\(\frac{0.07}{100}\) × 100)% = 7%

(d) 5\(\frac{1}{5}\)

Solution:

5\(\frac{1}{5}\) = \(\frac{26}{5}\)

= (\(\frac{26}{5}\) × 100)%

= 520%

Question 3.

Express as a fraction in the lowest term.

(a) 35%

Solution:

35% = \(\frac{35}{100}\) = \(\frac{7}{20}\)

(b) 16\(\frac{2}{3}\)%

Solution:

16\(\frac{2}{3}\)% = \(\frac{50}{3 \times 100}\) = \(\frac{1}{6}\)

(c) 2\(\frac{3}{4}\)%

Solution:

2\(\frac{3}{4}\)% = \(\frac{11}{4} \times \frac{1}{100}\) = \(\frac{11}{400}\)

(d) 90%

Solution:

90% = \(\frac{90}{100}\) = \(\frac{9}{10}\)

Question 4.

Express as a decimal.

(a) 71%

Solution:

71% = \(\frac{71}{100}\) = 0.71

(b) 9.5%

Solution:

9.5% = \(\frac{9.5}{100}\) = 0.095

(c) 101%

Solution:

101% = \(\frac{101}{100}\) = 1.01

(d) 759%

Solution:

759% = \(\frac{759}{100}\) = 7.59

Question 5.

Find the value of-

(a) 33\(\frac{1}{3}\)% of 429 metres

Solution:

33\(\frac{1}{3}\)% of 429 metres

= \(\frac{100}{3 \times 100}\) × 429

= 143 m

(b) 50% of 4 metres

Solution:

50% of 4 metres

= \(\frac{50}{100}\) × 4

= 2 m

(c) 100% of 200 grams

Solution:

100% of 200 grams

= \(\frac{100}{100}\) × 200

= 200 gm

(d) 20% of 1 kg

Solution:

20% of 1 kg

= \(\frac{20}{100}\) × 1

= \(\frac{1}{5}\)

= 0.2 kg or 200 gms

(e) 6\(\frac{1}{4}\)% of 1 litre

Solution:

6\(\frac{1}{4}\)% of 1 litre

= \(\frac{25}{4 \times 100}\) × 1

= \(\frac{1}{16}\) l

= 0.0625 l

(f) 12\(\frac{1}{2}\)% of ₹ 32

Solution:

12\(\frac{1}{2}\)% of ₹ 32

= \(\frac{25}{2 \times 100}\) × 32

= ₹ 4

Question 6.

A school contributed ₹ 3,500 to the flood relief fund. Sonal donated 10% of the fund. How much money was donated by Sonal?

Solution:

Total contribution of school = ₹ 3,500

Sonal’s contribution = 10%

Money contribution of Sonal = \(\frac{10}{100}\) × 3500 = ₹ 350

The money donated by Sonal was ₹ 350.

Question 7.

Mr Arun earns ₹ 35,500 per month. He spends 70% on household expenses, 25% on children, and saves the rest. How much money did Arun save?

Solution:

Earning of Mr Aran per month = ₹ 35,500

His expenditure = 70% + 25% = 95%

Saves = (100 – 95)% = 5%

His savings = \(\frac{5}{100}\) × 35500 = ₹ 1,775

Arun saved ₹ 1,775.

Question 8.

Mr Gupta took his family out for dinner. The amount of the bill was ₹ 875. Mr Gupta paid 5% of the bill amount as a tip. Find the money given as a tip.

Solution:

Amount of bill = ₹ 875

% of tip = 5%

Money as tip = 5% of ₹ 875

Amount paid at tip = \(\frac{5}{100}\) × 875 = ₹ 43.75

The money given as tip is ₹ 43.75.

Question 9.

Find the percentage of the letter ‘M’ in the word MATHEMATICS.

Solution:

Total alphabets = 11

% of ‘M’ = (\(\frac{2}{11}\) × 100)%

= (\(\frac{200}{11}\))%

= 18\(\frac{2}{11}\)%

Question 10.

Some numbers are below:

5, 2, 18, 26, 31, 42, 65, 7, 13, 35

Find the percentage of:

(a) Even numbers

(b) Odd numbers

(c) Prime numbers

(d) Odd primes

(e) Multiples of 5

(f) Even primes

Solution:

(a) Total numbers = 10

Even numbers = 4

% of even numbers = (\(\frac{4}{10}\) × 100)% = 40%

(b) Total numbers = 10

Odd numbers = 6

% of odd numbers = (\(\frac{6}{10}\) × 100)% = 60%

(c) Total number = 10

Prime numbers = 5

% of prime numbers = (\(\frac{5}{10}\) × 100)%

(d) Total numbers = 10

Odd prime numbers = 4

% of odd primes = (\(\frac{4}{10}\) × 100)% = 40%

(e) Total numbers = 10

Multiples of 5 = 3

% of multiples of 5 = (\(\frac{3}{10}\) × 100)% = 30%

(f) Total numbers = 10

Even primes = 1

% of even primes = (\(\frac{1}{10}\) × 100)% = 10%

Additional Questions

Question 1.

Complete the following:

(a)

Solution:

\(\frac{22}{100}\) = 22%

(b)

Solution:

\(\frac{133}{100}\) = 133%

(c)

Solution:

\(\frac{46}{100}\) = 46%

(d)

Solution:

\(\frac{89}{100}\) = 89%

(e)

Solution:

\(\frac{56}{100}\) = 56%

Question 2.

Convert the following percentages into fractions in the lowest term:

(a) 45%

Solution:

45% = \(\frac{45}{100}\) = \(\frac{9}{20}\)

(b) 125%

Solution:

125% = \(\frac{125}{100}\)

= \(\frac{5}{4}\)

= 1\(\frac{1}{4}\)

(c) 176%

Solution:

176% = \(\frac{176}{100}\)

= \(\frac{44}{25}\)

= 1\(\frac{19}{25}\)

(d) 89%

Solution:

89% = \(\frac{89}{100}\)

Question 3.

Express the following percentages into decimals:

(a) 8.8%

Solution:

8.8% = \(\frac{8.8}{100}\) = 0.088

(b) 8.9%

Solution:

8.9% = \(\frac{8.9}{100}\) = 0.089

(c) 2.9%

Solution:

2.9% = \(\frac{2.9}{100}\) = 0.029

(d) 0.38%

Solution:

0.38% = \(\frac{0.38}{100}\) = 0.0038

Question 4.

Convert the following into percentages.

(a) \(\frac{8}{25}\)

Solution:

\(\frac{8}{25}\) = (\(\frac{8}{25}\) × 100)% = 32%

(b) 3\(\frac{1}{4}\)

Solution:

3\(\frac{1}{4}\) = (\(\frac{13}{4}\) × 100)%

= (13 × 25)%

= 325%

Question 5.

Convert the following into percentages.

(a) 0.732

Solution:

0.732 = (0.732 × 100)% = 73.2%

(b) 3.7

Solution:

3.7 = (3.7 × 100)% = 370%

(c) 31.87

Solution:

31.87 = (31.87 × 100)% = 3187%

(d) 41.35

Solution:

41.35 = (41.35 × 100)% = 4135%

Question 6.

Find

(a) 20% of 800

Solution:

20% of 800 = \(\frac{20}{100}\) × 800 = 160

(b) 2\(\frac{1}{4}\)% of 160

Solution:

2\(\frac{1}{4}\)% of 160 = \(\frac{9}{4}\) × \(\frac{1}{100}\) × 160 = 3.6

(c) 2% of 400

Solution:

2% of 400 = \(\frac{2}{100}\) × 400 = 8