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A group of 55 students were asked if they had a cat or a dog. 11 were known to own both, 18 said they owned only a dog, and 34 said they owned at least a cat. Give the probability that a student has neither as a fraction in its simplest form.

ANSWER = 3/55
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Answered by Emily R. • Maths tutor
3206 Views

Solve the simultaneous equations: 3x+y=11 and 2x+y=8.

First we want to eliminate of one these variables in order to solve the equations. We need to identify which variable has the same coefficient- in this case, it is y. So, we subtract the two equations from e...
SK
Answered by Simran K. • Maths tutor
7271 Views

Find the equation to the tangent to the curve x=cos(2y+pi) at (0, pi/4)

Normally to find a tangent we want to work out dy/dx, but since this equation is x=something, it's much easier to work out dx/dy first, then we get dy/dx by doing 1/(dx/dy)=dy/dx. By the chain rule, dx/dy = ...
SJ
Answered by Sarah J. • Maths tutor
11877 Views

The probability of pulling out a coloured counter from a bag is shown below: Green=0.2. Purple=0.15. Black=0.3. Pink=?. What is the probability of pulling out a pink counter?

When we have a probability question with multiple possible outcome as we have here (the multiple possible outcomes are pulling out a green, purple, black or pink counter) the probabilities of all of these ou...
FA
Answered by Fauzia A. • Maths tutor
4563 Views

Solve 3x²+6x-7=0 by using completing the square method. Leave your answer in surd form.

This is a question which is simply asking you to solve a quadratic. There are three main ways to do this; quadratic equation, factorising into brackets and completing the square. As the question specifically...
SS
Answered by Sunny S. • Maths tutor
6325 Views