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In a bag of 72 red and green marbles, 5/9 are green. What is the number of red marbles in the bag?

72 cards5/9 are green = 72/(5/9) = 40 green marbles72 - 40 = 32 red marbles
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Answered by Venn S. • Maths tutor
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The student did another experiment using 20 cm3 of sodium hydroxide solution with a concentration of 0.18 mol/dm3 . Relative formula mass (Mr) of NaOH = 40 Calculate the mass of sodium hydroxide in 20 cm3 of this solution.

20/1000 *0.18 final answer 0.144 Answer must be explained in person. It is very difficult to explain in writing.
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Answered by Saranya G. • Chemistry tutor
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Why is the nos form of 'jugar', spelt 'jugamos' and not 'juegamos'

The nos form of 'jugar' is spelt 'jugamos' and not 'juegamos' because it is a radical changing verb. This means that the stem of the verb does not stay the same as it would with regular verbs, such as comer ...
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Answered by Hannah B. • Spanish tutor
7166 Views

A compound is found to contain 3.1% Hydrogen, 65.3% Oxygen and 31.6% Phosphorus. Work out its empirical formula.

To answer this question, we need to know the relative number of atoms of each element present. This can be calculated by dividing the amount of an element present in the sample by the relative masses of that...
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Answered by Adam B. • Chemistry tutor
6657 Views

What are the non-specific defence systems of the body against pathogens?

There are four main non-specific defence systems, all of which are immediate and the same for all pathogens (hence 'non-specific).1) skin: it acts as a primary defence mechanism as the dry, dead cells on the...
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