Question

Q.3 Name the following:
1. The silvery residue obtained on heating mercury [II] oxide Mercure
2. The gas evolved when a dilute acid is added to chalk [limestone)
3. Two non-metals which react explosively when brought in close contact
4. Two gases which react under pressure in presence of a catalyst at elevated
temperatures to give a gaseous product.
5. A catalyst which increases the rate of a chemical reaction
please answer the correct answer​

Answer 1

Given :-

75% of total 1500 are boys.

⅓ are boys

And No. of girls = 40%

To find :-

Total students

Solution :-

No. of boys :-

75% of 1500

75/100 × 1500

75 × 15

1125 boys

Now,

Numbers of girls = 1500 - 1125

=> 375

Total spectacles =>

⅓ × 1125

375

In girls

40/100 × 375

4/10 × 375

150

Total students that wear spectacles = 150 + 375 = 525

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