Exercise 6.4

1. In a school X, 48 students appeared for 10th class exam out of which 36 students passed. In another school Y, 30 students appeared and 24 students passed. If the District Educational Officer wants to give an award on the basis of pass percentage. To which school will he give the award?

Solution:

Given:

School X:

Total students =

Passed students =

Let's find pass percentage of school X:

Pass percentage = (No. of students passed / Total students) × 100

= × 100

= × 100

= %

School Y:

Total students =

Passed students =

Let's find pass percentage of school Y:

Pass percentage = (No. of students passed / Total students) × 100

= × 100

= × 100

= %

Comparing the pass percentages:

School X = 75% School Y = 80%

Since 80% > 75%

Therefore, the District Educational Officer will give the award to School

2. Last year the cost of 1000 articles was ₹5000. This year it goes down to ₹4000. What is the percentage of decrease in price?

Solution:

Given:

Original price =

New price =

Let's find the decrease in price:

Decrease = Original price - New price

= 5000 - 4000 =

Let's find percentage of decrease:

Percentage of decrease = (Change in price / Original Price) × 100

= × 100

= × 100

= %

Therefore, the percentage of decrease in price is 20%

3. 64% + 20% + .....? = 100%

Solution:

Given:

64% + 20% + ? = %

Let's first add known percentages:

64% + 20% = %

To find missing percentage:

100% - 84% = %

Therefore, the missing percentage is 16%

4. Sri Jyothi has a basket full of bananas, oranges and mangoes. If 50% are bananas, 15% are oranges, then what percent are mangoes?

Solution:

Given:

Percentage of bananas = %

Percentage of oranges = %

Let's solve step by step:

Total percentage of all fruits = %

Percentage of bananas and oranges = 50% + 15%

= %

Percentage of mangoes = 100% - 65%

= %

Therefore, 35% are mangoes

5. On a rainy day, out of 150 students in a school 25 were absent. Find the percentage of students absent from the school? What percentage of students are present?

Solution:

Given:

Total students =

Absent students =

Let's find present students:

Present students = 150 - 25 =

Let's find percentage of absent students:

Percentage of absent students = (Absent students / Total students) × 100

= × 100

= %

Let's find percentage of present students:

Percentage of present students = (Present students / Total students) × 100

= × 100

= %

Therefore:

• Percentage of students absent = 16.67%
• Percentage of students present = 83.33%

6. Out of 12000 voters in a constituency, 60% voted. Find the number of people voted in the constituency?

Solution:

Given:

Total voters =

Percentage voted = %

Let's find number of people who voted:

Number of people voted = (Percentage voted / 100) × Total voters

= × 12000

= × 12000

=

Therefore, 7200 people voted in the constituency

7. A local cricket team played 20 matches in one season. If it won 25% of them and lost rest. How many matches did it loose?

Solution:

Given:

Total matches =

Won percentage = %

Let's find lost percentage:

Lost percentage = 100% - 25%

= %

Let's find number of matches lost:

Number of matches lost = (Lost percentage / 100) × Total matches

= × 20

= × 20

=

Therefore, the team lost 15 matches

8. In every gram of gold, a goldsmith mixes 0.25 grams of silver and 0.05 grams of copper. What is the percentage of gold, silver and copper in every gram of gold?

Solution:

Given:

Silver = grams

Copper = grams

Let's find total mixed metals:

Total mixed metals = 0.25 + 0.05 = grams

Amount of gold = 1 - 0.30 = grams

Let's find percentages:

Percentage of gold = × 100

= %

Percentage of silver = × 100

= %

Percentage of copper = × 100

= %

Therefore:

• Gold = 70%
• Silver = 25%
• Copper = 5%

9. 40% of a number is 800 then find the number?

Solution:

Given:

40% of number =

Let's solve step by step:

Let the number be x

Then: × x = 800

x = 800 ×

x =

Therefore, the number is 2000