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There are 12 counters in a box, 5 red and 7 blue. 2 counters are taken out at random without replacement, what is the probability that they are the same colour?

We need to consider two possibilities, you could either pick out two blues or two reds. To find the total probability we work it out for each individually and then add them together. We can find the probabil...
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Answered by Christopher R. • Maths tutor
5956 Views

A car costs £1200 in a sale. It was reduced by 20%. What was the original price?

£1200 is 80% of the original price.We need to find what 100% of the original price is.if £1200 is 80% then to find 1% we can divide it by 80. 1200/80=15 £15 is 1% of the original price to find 100% we can mu...
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Answered by Luke F. • Maths tutor
6405 Views

A curve has an equation: (2x^2)*y +2x + 4y – cos(pi*y) = 17. Find dy/dx

You must differentiate each individual term in the equation.Firstly start with the term of the product of 2x 2 * y, using the product rule (dy/dx = u dv/dx + v du/dx)Let u = 2x 2 and v = yDu/dx = 4x and dv/d...
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Answered by Matthew B. • Maths tutor
4054 Views

A curve f(x,y) is defined by sin(3y)+3ye^(-2x)+2x^2 = 5. Find dy/dx

In questions where we have a function of x and y equal to a constant, we need to find dy/dx indirectly.We use the formula (df/dx) + (df/dy)(dy/dx) = 0So all we do is differentiate each term in the function w...
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Answered by Lewie W. • Maths tutor
4130 Views

Consider the closed curve between 0 <= theta < 2pi given by r(theta) = 6 + alpha sin theta, where alpha is some real constant strictly between 0 and 6. The area in this closed curve is 97pi/2. Calculate the value of alpha.

Student uses the definition of area [A = 1/2 integral r(theta)^2 d theta], and proceeds using standard integration techniques to give a quadratic solvable for alpha. [alpha^2 = 25] Thus, alpha = 5.
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Answered by Graham C. • Maths tutor
3936 Views