A
What is the boiling point of pure water in kelvin?
373 K
What does DNA code instruct the cell to make?
Protein
Which gas is responsible for the "rotten egg" smell?
Hydrogen sulfide (H2S)
How many water molecules are present in one molecule of washing soda?
10
What is a class of plant growth substances (often called phyto hormones) which play an essential role in coordination of many growth and behavioral processes in the plant life cycle?
auxin
What is any physical law stating that a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity?
inverse square law
Which element is essential for the process of blood clotting?
Calcium
Which gas is filled in an electric bulb?
Nitrogen gas
What is a chemical reaction between two compounds where the positive ion of one compound is exchanged with the positive ion of another compound?
double replacement reaction
Which type of biomolecule is primarily used for long-term energy storage in the body?
Lipids
What are the dimensions of a joule, the S.I. unit for measuring energy?
kg m2s-2
what is a relationship between two species of organisms in which both benefit from the association?
mutualism / symbiosis
The price of an item increases by 20% and then decreases by 20%. What is the net effect on the price?
Decreased by 4%
Explanation
When the price of an item increases by 20% and then decreases by 20%, the net effect is a decrease in the overall price. Here’s how it works:
Initial Price: Assume the original price is $100.
After 20% Increase:
New price = $100 + 20% of $100 = $100 + $20 = $120.
After 20% Decrease:
New price = $120 - 20% of $120 = $120 - $24 = $96.
So, the net effect is a 4% decrease in the original price. The final price is $96, which is less than the original price.
What is the next number in the sequence: 3, 7, 15, 31,?
63
18) In ∆ ABC, AB = AC and ∠B = 50°. Then ∠C is equal to:
50°
Explanation:
Given that, in a triangle ABC, AB = AC and ∠B = 50°.
Since the given triangle is an isosceles triangle, the angles opposite to the equal sides are also equal. Hence, ∠C = 50°.
The ratio of girls to boys in a school is 5:7. If there are 525 girls, how many boys are there?
735
Explanation
The ratio of girls to boys in the school is 5:7. This means for every 5 girls, there are 7 boys. Given there are 525 girls, we first determine how many times the part of the ratio (5) fits into the actual number of girls (525).
Calculate the multiplier for the ratio:
525 (number of girls) / 5 (girl ratio part) = 105
Now, use this multiplier to find the number of boys:
Multiply the boy ratio part by the multiplier:
7 (boy ratio part) x 105 (multiplier) = 735
Therefore, there are 735 boys in the school.