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A bag contains only apple and oranges. The probability an apple is picked randomly is 1 in 5. The apple is returned, and five more apples are added to the bag. The probability of an apple being picked is now 1in 3. How many apples were there originally?

2 simultaneous unknown equations. Let x be the number of apples originally, and n the number of fruits in the bag in total originally. i) first scenario, where probability is 1/5, x/n = 1/5 5x= n ii) second ...
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Answered by Chloe L. • Maths tutor
4306 Views

differentiate with respect to x : y = x^2 -5x

to find dy/dx, multiply each item by the power of the x, and then decrease the power of the x by 1.Step 1 : 2 x^2 -1 5x (multiplying by power of x)Step 2 : 2 x^1 -1 5x^0Therefore:dy/dx = 2x - 5.
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Answered by Branwen A. • Maths tutor
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solve this simultaneous equation: 2x + 3y = 19 (Eq1) and 3x + y = 11 (Eq2)

Begin by multiplying the second equation by three in order to get a 3y value: 9x + 3y = 33. We can now subtract equation one from equation two, 9x + 3y = 33 and 2x + 3y = 19 -->7x + 0y = 14. Resulting in,...
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Answered by Tomas B. • Maths tutor
4969 Views

How to divide or multiply by 10s, 100s, 1000s

When dividing a number, the number gets smaller . So, the decimal point moves towards the left . However, when you are multiplying a number, the number gets bigger . So, the decimal point moves towards the r...
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Answered by Adila M. • Maths tutor
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How do we use ratios to figure out how much money to give to people of a lump sum?

Lets start with an example scenario:Two people are to receive a percentage of a £500 business sale. One receives 25% and the other receives 75%. When using percentages we must remember that it means it is pe...
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Answered by Daniel C. • Maths tutor
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