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If the probability of picking a red ball out of bag A is 2/5 and the probability of picking a red ball out of bag B is 3/7, what is the chance that you will pick exactly 2 red balls if you pick 2 balls from A and 1 ball from B? The balls are not replaced.

Draw a tree diagram. Recognise that the second ball selected from bag A is dependent on the outcome of the first ball. The outcome of the ball selected from B is independent. There are 3 orders that 2 red ba...
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Answered by Nicky M. • Maths tutor
4917 Views

How do you factorise x^2 - 4?

x^2 - 4 consider that in any quadratic the two numbers which end up in the brackets at the end must add up to the middle term in x. they must also multiply to make the number at the end of the quadratic term...
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Answered by Zachary M. • Maths tutor
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Show that (x+1)(x+2)(x+3) can be written in the form ax^3 +bx^2 + cx + d where a,b,c,d are positive integers.

First we shall expand two of the brackets to obtain a quadratic equation and then multiply each term by the remaining bracket. The order with which we expand the brackets does not matter. Use the FOIL method...
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Answered by Scott W. • Maths tutor
10206 Views

Tom thinks of a number. He squares it, adds 3 times the original number and then subtracts 18. The result is 0. What two numbers could Tom have been thinking of?

Formulate the problem algebraically:x 2 +3x-18=0This is a factorisation problem. To find the solutions, factorise:-Factors of x 2 are 1 and 1 , so answer will take the form: (x +- ?)(x +- ?)=0-List pairs of ...
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Answered by George H. • Maths tutor
4153 Views

Prove that the square of an odd number is always 1 more than a multiple of 4

This is a nice little question off the 2018 Edexcel Higher Maths paper! When we heard the word 'prove' in a question at this level, automatically we should be thinking about using algebra to help us out! Fir...
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Answered by Thomas R. • Maths tutor
3934 Views