Answer:
The word "of" in the question means multiply, so you need to multiple these two fractions.
2/3 x 4/5 = 8/15
First let’s multiply. 8x-4=-3x+32. Start collecting like terms on different sides. 8x+3x=32+4. 11x=36. x=36/11. x=3.27.
The given data is
Scores: 90-99 80-89 70-79 60-69 50-59
Students: 3 7 12 4 4
Because we are to take the middle value for each group.
Therefore the total score is
Sx = 3*94.5 + 7*84.5 + 12*74.5 + 4*64.5 + 4*54.5 = 2245
The number of students is 3+7+12+4+4 = 30
The mean is
m =2245/30 = 74.833
Calculate (Sx - m)²
(Sx - m)² = 3*(94.5-74.833)² + 7*(84.5-74.833)² + 12*(64.5-74.833)²
+ 4*(64.5-74.833)² + 4*(54.5-74.833)² = 3896.7
Calculate the standard deviation
s = √(3896.7/29) = 11.592
Answer:
mean = 74.83
std. deviation = 11.59
The ratio of the number of minutes he lifter weights tot the total minutes he worked out is 25: 50. Simplified, the ratio would be 1:2
I’ve attached my work!
Hope it helps :)
If you have any questions or anymore help lmk, happy to help with any school work!!
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