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In a stack of CDs, there are 3 types: Rock, Pop and Jazz. There are 2 Rock CDs, x Pop CDs, and (2x+5) Jazz CDs. A CD is chosen at random. If the probability it is Rock is 1/20, work out the probability it is Jazz.

Number of Rock CDs = 2Total Number of CDs = 2 + x + (2x+5) = 3x + 7Probability of Rock CD = 2/(3x + 7) = 1/202/(3x + 7) = 1/2040 = 3x + 7x = 11Number of Jazz CDs = 2x + 5 = 27Total Number of CDs = 3x + 7 ...

Answered by Vinh L. • Maths tutor

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The perimeter of a right-angled triangle is 72 cm. The lengths of its sides are in the ratio 3 : 4 : 5 Work out the area of the triangle.

3+4+5=12
72/12=6
36= 18 46=24 56=30
Area of a right-angled triangle= ab/2
18240.5= 216

Answered by Saif K. • Maths tutor

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

An odd number can be expressed by the formula "2n + 1" where n stands for any integer. Therefore, the square of any odd number can be expressed as:(2n+1)^2 = (2n+1)(2n+1) = 4n^2 + 4n + 1 = 4(n^2...

Answered by Edward B. • Maths tutor

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What is the range of the function y = x^2?

Every mathematical function has a range and a domain. The range of a function is the set of possible outputs the function has. In this case, we know that our output (y) must be a positive number because i...

Answered by Molly B. • Maths tutor

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Solve the following quadratic equation by factorization. Show your working.

4x²+20x+8=-16First add 16 to both sides of the equation, this gives 4x²+20x+24=0 We always want to set the equation =0 for a quadratic as we are unable to solve it otherwise.Then we ...

Answered by Lauren O. • Maths tutor

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