Question 867768
the average (arithmetic mean) of 10 exam grades is 87.if the highest and lowest grades are removed from the set, the average of the remaining 8 exam grades is 90. what was the average of the 2 exam grades that were removed?
Let h = the high grade
let L = the lowest grade
the other 8 average 90
the equation
{{{(L + 8(90) + h)/10}}} = 87
multiply both sides by 10
L + 720 + h = 870
L + h = 870 - 720
L + h = 150
therefore: {{{150/2}}} = 75 is the average of the 2 removed grades
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circle A has a circumference of 4pi, and circle b has a circumference of 8pi. if the circles intersect at two points , what is a possible distance from the center of circle A to the center of circle B?
Find the radius of Circle A
{{{2pi*r}}} = {{{4pi}}}
2r = r
r = 2
Find the radius of Circle b
{{{2pi*r}}} = {{{8pi}}}
r = 4
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Place A's center on the circumference of b, the centers would be 4 units apart