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There are N counters in a bag, 4 being red and the rest being blue. I take two counters at random from the bag (without replacing the first).The chance i take two blue counters is 1/3, See below in the answer box

Show that n^2-13n+30=0We note that 4/N denotes the probability of a me picking a red counter and (N-4)/N denotes the chance of me picking a blue counter.Since I select two counters and do not replace the fir...
RP
Answered by Roshan P. • Maths tutor
8271 Views

pH and Kw question: A student dissolves 1.75g of a drain cleaner (based on NaOH) in water and makes the solution up to 100cm3. The student measures the solution pH as 13.60. Determine the percentage of NaOH in the drain cleaner, in terms of mass (g).

[H + ] = 10 -pH , so [H + ] = 10 -13.6 = 2.5 x 10 -14 moldm -3 . pH=-log 10 ([H + ]), so we have rearranged this to make [H + ] the subject of the formula. K w = [H + ] x [OH - ] = 1.0 x 10 -14 moldm -3 . Th...
LN
Answered by Laura N. • Chemistry tutor
7698 Views

Cube roots of 8?

8 traditionally has 1 cube root. 2. This is only the real root. It has 2 more complex roots!How can we see this?Consider a vector on the argand diagram. If we square it. What happens to it's magnitude and ar...
VJ
4601 Views

Find the gradient at x=1 for the curve y=2x*e^2x

The answer to this question is in two parts. We firstly must find the derivative of the function y=f(x) with respect to x, and then substitute the value of x given in the question to find the gradient at tha...
DD
Answered by Dominic D. • Maths tutor
4985 Views

Describe the process of atherosclerosis and the effect it has on the properties of the blood vessel

Atherosclerosis occurs when the endothelium of a blood vessel becomes damaged. This may due to various reasons such as high blood pressure or toxins from cigarette smoke. This causes an inflammatory response...
LT
Answered by Laura T. • Biology tutor
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