TRY THESE Homework Help Survey Analysis,comparing quantities class 8,

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Homework Help Survey Analysis

In a primary school, the parents were asked about the number of hours they spend per day in helping their children to do homework. There were 90 parents who helped for 1 2 hour to 1 1 2 hours.

The distribution of parents according to the time for which they said they helped is given in the adjoining figure:

• 20% helped for more than 1 1 2 hours per day
• 30% helped for 1 2 hour to 1 1 2 hours
• 50% did not help at all

50% - Did not help at all

30% - Helped for 1 2 hour to 1 1 2 hour

20% - Helped for more than 1 1 2 hour

Answer the Following Questions:

(i) How many parents were surveyed?

(ii) How many said that they did not help?

(iii) How many said that they helped for more than 1 1 2 hours?

📝 Detailed Solutions

Solution (i): How many parents were surveyed?

Given: 90 parents = 30% of total

30% of Total = 90
0.30 × Total = 90
Total = 90 ÷ 0.30
Total = 90 ÷ (30/100)
Total = 90 × (100/30)
Total = 90 × 3.333...
Total = 300 parents

Alternative Method:

If 30% → 90 parents
Then 10% → 90 ÷ 3 = 30 parents
And 100% → 30 × 10 = 300 parents

Solution (ii): How many said they did not help?

Given: Total = 300 parents, 50% did not help

Number who didn't help = 50% of 300
= 0.50 × 300
= 150 parents

Alternative Method:

50% = 1 2 (half)
Half of 300 = 300 ÷ 2 = 150 parents

Solution (iii): How many helped for more than 1½ hours?

Given: Total = 300 parents, 20% helped more than 1½ hours

Number = 20% of 300
= 0.20 × 300
= 60 parents

Alternative Method:

20% = 1 5 (one-fifth)
One-fifth of 300 = 300 ÷ 5 = 60 parents

✓ Verification

Let's check if all categories add up to 300:

Did not help: 150 parents (50%)
Helped 1 2 to 1 1 2 hours: 90 parents (30%)
Helped more than 1 1 2 hours: 60 parents (20%)
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Total: 150 + 90 + 60 = 300 ✓
Percentages: 50% + 30% + 20% = 100% ✓