1.There are 20 students in a class. The average for that class on a test was computed as 74, but one student's grade was read mistakenly as 50 instead of 90. What will the average grade for that class be when it is recomputed using the corrected score?
2.Find the perimeter of a square with area 625 square inches.
3.Two students in a class of 18 have braided hair. Predict the total number of students with braided hair if there are 360 students in the senior class.
2006-11-29 14:15:49 · 6 answers · asked by Felicia F 1 in Science & Mathematics ➔ Mathematics
The average was (90-50)/20 = 2 lower than it should have been; thus 76.
Side length = sqrt(625) = 25, so 4*25 = 100 inches.
2/18 * 360 = 40.
2006-11-29 14:20:20 · answer #1 · answered by stephen m 4 · 0⤊ 0⤋
1.
(90 - 50) / 20 = 2
So the average is: 74 + 2 = 76
2.
sqrt(625) = 25
-> the perimeter of a square with area 625 square inches is
4*25=100 inch
2006-11-29 14:18:38 · answer #2 · answered by can_t_get_enough 2 · 0⤊ 0⤋
average of 20 students=74
total marks=average*no ofstudents
=1480
less marks wronkly read=50
add the correct marks=90
correct total=1480-50+90
=1520
correct average=correct total/o of students
=1520/20=76
2.perimeter os square=4 times the side
side of the square=square root of 625
=25 in.
perimeter=4*25
=100 in.
3.prediction=probability*no of students
probability=favourable events/sample space
=2/18
=1/9
so prediction=360(1/9)
=40
2006-11-29 14:21:53 · answer #3 · answered by raj 7 · 0⤊ 0⤋
1) 20x74-50+90=76
2) root 625X4 = 25x4=100
3) 2x360/18=40
2006-11-29 14:24:36 · answer #4 · answered by loveboy 5 · 0⤊ 0⤋
2. 100 inches
3. is a simple ration 2:18 as x:360 (360/18)x2 = answer
2006-11-29 14:20:41 · answer #5 · answered by Matt B 2 · 0⤊ 0⤋
next time..
i think the answer is 1,000,000 though
2006-11-29 14:22:52 · answer #6 · answered by tep 2 · 0⤊ 0⤋