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If a bag contains 6 green balls and 3 red balls, what the probability of picking out 2 red, with and without replacement.

For the first ball the probability we pick a red ball is the same, it's the number of red balls divided by the total number of balls. Which in this case is 3/9. If we replace the balls the chance of picking ...
TF
Answered by Toby F. • Maths tutor
23268 Views

Remove the brackets: −{−2[x−3(y−4)]−5(z+6)}

First Step: - {-2[x-3y+12]-5z-30} Second Step: - {-2x+6y-24-5z-30} Third Step (Order is x,y, then z) : - {-2x+6y-5z-54} Final Step: 2x-6y+5z+30
VZ
Answered by Victoria Z. • Maths tutor
5555 Views

How do I solve simultaenous equations? e.g. 2x -5y =11 and 3x+2y=7

Step 1: Multiply both equations together so that the multiples of one of the unknown terms are the same or the negative of that number. This will allow you to add/subtract the two equations to eliminate one ...
MK
Answered by Matthew K. • Maths tutor
3712 Views

Find the area of a circle with a diameter of 4cm.

The diameter of a circle is the longest measurement across the circle, and is a straight line passing through the middle. Half of this line is the radius, which is a straight line from the centre of the circ...
SS
Answered by Sabrina S. • Maths tutor
18803 Views

When do I use the Sine rule?

You use the sine rule (a/sina=b/sinb) when you know 2 angles and one side amd you want to find out what the length of the side opposite one of the angles is.
ES
Answered by Edward S. • Maths tutor
4164 Views