Answer: Jiří is 5 years old.
Step by step:
Let x denote Jiří's age in years. Then Pamela's age is 3x. Their sum is x + 3x = 20. So we solve for x:
x + 3x = 20
4x = 20
x = 5
Jiří's age is 5 years
It is c. If you do the equation it is -1 1/4
<span>0.9% glucose solution means there are 0.9 g of glucose per 100 mL water.
</span><span> The concentration is required per litre for molar concentration:
0.9% glucose solution contains 9 g of glucose per 1000 mL or 1 L of water.
Molar mass of glucose is 180.16 g mol^-1 so 9 g = 9g/180.16 g mol^-1 = 0.05 moles
</span><span> 1 L of water contains 0.05 moles of glucose so molar concentration is 0.05 M or 0.05 mol/L </span>
1. B
2. D
3. I don't know
4. C
