The following table shows the salary of 7 people in an office last year. Name Income Andy £9500 Bevan £25000 Cheryl £11250 Deva £72000 Elliott £12750 Frankie £29500 Grace £11000 a) Work out the mean income to 2 DP. b) Deva was given a large bonus for 30 years service. Excluding Deva's income, what was the mean income for the remaining 6 workers to 2 DP?

Use the distance formula to find the distance between (-3,5) and (3,1)

Aprisoner is trapped in a cell containing three doors. the first door leads to a tunnel that returns him to his cell after two days of travel. the second leads to a tunnel that returns him to his cell after three days of travel. the third door leads immediately to freedom. (a) assuming that the prisoner will always select doors 1, 2 and 3 with probabili- ties 0.5,0.3,0.2 (respectively), what is the expected number of days until he reaches freedom? (b) assuming that the prisoner is always equally likely to choose among those doors that he has not used, what is the expected number of days until he reaches freedom? (in this version, if the prisoner initially tries door 1, for example, then when he returns to the cell, he will now select only from doors 2 and 3.) (c) for parts (a) and (b), find the variance of the number of days until the prisoner reaches freedom. hint for part (b): define ni to be the number of additional days the prisoner spends after initially choosing door i and returning to his cell.

Find the axis symmetry of x y=4x-6x+3