A unit of gas costs 4.2 pence.
On average Ria uses 50.1 units of gas a week.
She pays for the gas she uses in 13 weeks.
.
(a) Work out an estimate for the amount Ria pays.
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Use the inverse of the function y=x^2-18x to find the unknown value [tex]y = \sqrt{bx + c \: + d} [/tex]

Which function has the same domain as y=2x

Let the mean of the population be 38 instances of from 6" - 9" hatchings per nest, and let the standard deviation of the mean be 3. what sample mean would have a confidence level of 95% or a 2.5% margin of error?